71 entries found for : it-10
Nguyen KL, Lamerand SR, Deshpande RP, Taylor BK (2021) Featured Article: Selective ablation of IB4+ primary afferent neurons reduces mechanical and cold hyperalgesia in an EAE mouse model of multiple sclerosis. Targeting Trends 22
Related Products: IB4-SAP (Cat. #IT-10), Blank-SAP (Cat. #IT-21)
Read the featured article in Targeting Trends.
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A spinal microglia population involved in remitting and relapsing neuropathic pain
Kohno K, Shirasaka R, Yoshihara K, Mikuriya S, Tanaka K, Takanami K, Inoue K, Sakamoto H, Ohkawa Y, Masuda T, Tsuda M (2022) A spinal microglia population involved in remitting and relapsing neuropathic pain. Science 376(6588):86-90. doi: 10.1126/science.abf6805
Objective: To investigate pain recovery mechanisms.
Summary: The authors reveal a mechanism for the remission and recurrence ofneuropathic pain, providing potential targets for therapeutic strategies.
Usage: The dose of CTB-SAP and IB4-SAP was 8 ug/10 uL, diluted in PBS.
Related Products: CTB-SAP (Cat. #IT-14), IB4-SAP (Cat. #IT-10)
Nguyen KL, Lamerand SR, Deshpande RP, Taylor BK (2021) Contribution of small diameter non-peptidergic primary afferent neurons to central neuropathic pain in a new, more clinically relevant mouse model of multiple sclerosis. Neuroscience 2021 Abstracts P377/07. Society for Neuroscience, Virtual.
Summary: Over 50% of multiple sclerosis (MS) patients suffer from neuropathic pain (MSNP). Current treatments give inadequate relief due to incomplete understanding of underlying mechanisms. Recent electrophysiological recordings of primary afferent neurons (PAN) in the dorsal root ganglion (DRG) following experimental autoimmune encephalomyelitis (EAE), a mouse model of MS, revealed increased afterhyperpolarization in small-diameter fibers. These data form the premise of our goal to understand the contribution of small-diameter (peptidergic or non-peptidergic) PANs to MSNP. Arguably the most common method to induce EAE is administration of myelin oligodendrocyte glycoprotein (MOG) to generate an autoimmune response targeting the myelin sheath. A MOG fragment is typically given with two adjuvants: complete Freund’s adjuvant (CFA) to boost immunogenicity and pertussis toxin (PTX) to breakdown the blood-brain barrier and facilitate CNS immune cell infiltration. However, PTX can disrupt G-protein coupled receptors, cause pain, and alter autoimmune response gene expression. In 10-week-old C57BL/6 mice, we conducted the first rigorous comparison of a classic PTX EAE model with the novel non-PTX (nPTX) EAE model. We found that both PTX and nPTX EAE mouse models showed the same degree of: 1) motor deficits; 2) plantar hindpaw mechanical and cold hypersensitivity (except cold hypersensitivity resolved more quickly after PTX EAE than nPTX EAE); and 3) lumbar spinal cord demyelination. Unlike most rodent models of MS including PTX EAE, the nPTX EAE group exhibited somatosensory cortex demyelination, a core feature of MS in human patients and cold hypersensitivity. We suggest nPTX EAE to be the most clinically relevant rodent model available to study not only MSNP, but MS in general. To evaluate the contribution of peptidergic and non-peptidergic neurons to MSNP, we induced nPTX EAE. After 12 days we administered capsaicin (10µg/mouse, i.t.) or IB4-saporin (1.5µg/mouse, i.t.) to primarily ablate peptidergic or nonpeptidergic C-fibers, respectively. Ablation efficacy was successfully confirmed with dramatic loss in DRG of TRPV1/CGRP immunoreactivity (peptidergic C-fibers) following capsaicin, and IB4 immunoreactivity (nonpeptidergic C-fibers) following IB4-saporin. IB4-saporin, but not capsaicin, partially reduced mechanical hypersensitivity and reversed cold hypersensitivity within 9 days. These data suggest nonpeptidergic but not peptidergic C-fibers contribute to MSNP. Our next studies will use genetic knockout, chemogenetic, and optogenetic strategies using MrgprdCreER mice to modulate the activity of nonpeptidergic C-fibers.
Related Products: IB4-SAP (Cat. #IT-10)
Nociception impedes grasping recovery in the spinal cord injured rat.
Walker J, Kim T, Giszter S, Detloff MR (2021) Nociception impedes grasping recovery in the spinal cord injured rat. Neuroscience 2021 Abstracts P372.04. Society for Neuroscience, Virtual.
Related Products: IB4-SAP (Cat. #IT-10)
de Almeida AS, Bernardes LB, Trevisan G (2021) TRP channels in cancer pain. Eur J Pharmacol 904:174185. doi: 10.1016/j.ejphar.2021.174185
Objective: To describe the role of TRP vanilloid 1 (TRPV1) and TRP ankyrin 1 (TRPA1) involved in cancer pain mechanisms.
Summary: Several studies have revealed that the administration of TRPV1 or TRPA1 agonists/antagonists and TRPV1 or TRPA1 knockdown reduced sensitivity to nociception in cancer pain models. Thus, TRP channels are potential targets for managing cancer-related pain syndromes.
Usage: Ablation of IB4 (+) neurons.
Related Products: IB4-SAP (Cat. #IT-10)
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Studying human nociceptors: from fundamentals to clinic
Middleton SJ, Barry AM, Comini M, Li Y, Ray PR, Shiers S, Themistocleous AC, Uhelski ML, Yang X, Dougherty PM, Price TJ, Bennett DL (2021) Studying human nociceptors: from fundamentals to clinic. Brain 144(5):1312-1335. doi: 10.1093/brain/awab048Summary: The authors injected 5 µg of IB4-SAP into the sciatic nerve in the left thigh. Lesioned animals displayed attenuated NGF-induced hyperalgesia, as well as differences in other pain-model markers.
Related Products: IB4-SAP (Cat. #IT-10)
Antiplexin D1 antibodies relate to small fiber neuropathy and induce neuropathic pain in animals
Fujii T, Lee EJ, Miyachi Y, Yamasaki R, Lim YM, Iinuma K, Sakoda A, Kim KK, Kira JI (2021) Antiplexin D1 antibodies relate to small fiber neuropathy and induce neuropathic pain in animals. Neurol Neuroimmunol Neuroinflamm 8(5):e1028. doi: 10.1212/NXI.0000000000001028Summary: NeP patient-derived plexin D1-IgG selectively binds to isolectin B4-positive unmyelinated C-fiber type small DRG neurons that sense mechanical pain.
Related Products: IB4-SAP (Cat. #IT-10)
Sato M, Saitoh I, Akasaka E, Inada E (2021) Development of a novel pipette tip-aided cell cloning method for the effective isolation of genome-edited porcine cell. OBM Genetics 5(1):16. doi: 10.21926/obm.genet.2101126Summary: Isolation of clonal cells from a single colony is an essential step in the process of obtaining pure populations of stably-transfected clones after gene transfer and the subsequent drug selection. In the present study, a novel, simple, and non-invasive technique for the isolation of cells from single colonies using a disposable pipette tip was developed.
Usage: A toxin-based, drug-free selection system involving IB4-SAP was employed in the present study.
Related Products: IB4-SAP (Cat. #IT-10)
Walker JR, Ong A, Detloff MR (2019) Role of nociceptive afferent input on forelimb reaching and grasping behaviors in the spinal cord injured rat. Neuroscience 2019 Abstracts 572.09. Society for Neuroscience, Chicago, IL.
Summary: Individuals with spinal cord injury (SCI) suffer a loss of motor and sensory function. The current standard of care to recover fine motor control is rehabilitation focused on a combination of range of motion, aerobic, and strength training (ST). However, limited research has been conducted to determine the role of nociceptive afferent inputs from muscle on spinal plasticity and/or recovery of function. Using a rodent model of SCI strength training rehabilitation, we determined that motor training not only improves forelimb strength and fine motor function but also can modulate the development of neuropathic pain, suggesting that improvements in reaching and grasping may be due, in part, to plasticity of nociceptive afferents. To further explore this, Sprague-Dawley rats received injections of rIB4-conjugated saporin, mu p75-conjugated saporin or unconjugated (vehicle) into the cervical dorsal root ganglia unilaterally to eliminate non-peptidergic and peptidergic nociceptors. There is an uninjured cohort and a group with unilateral C5 SCI. Von Frey and Hargreaves’ tests were performed at baseline and several time points post-injection to assess the effcacy of the nociceptive elimination. Several measures of forelimb strength were recorded over time including the isometric pull task, a single pellet retrieval task and the Montoya staircase test. To confirm the depletion of peptidergic and non-peptidergic nociceptors following saporin injection and/or SCI, cervical DRGs and spinal cords were stained with antibodies against CGRP and isolectin-B4. An understanding of the role of nociceptors in spinal plasticity and functional motor and sensory recovery of SCI patients will guide future research and refine rehabilitation strategies to further improve their quality of life.
Related Products: IB4-SAP (Cat. #IT-10), mu p75-SAP (Cat. #IT-16)
A high efficacy selection method for transfected cells utilizing recombinant isolectin B4-saporin
Galvan MA, Shramm PA, Bouajram R, Lappi DA, Ancheta LR (2019) A high efficacy selection method for transfected cells utilizing recombinant isolectin B4-saporin. Neuroscience 2019 Abstracts 794.10. Society for Neuroscience, Chicago, IL.
Summary: Transfection protocols often rely on the use of antibiotics for the selection of transfected cells and has become the accepted approach for in vitro research and therapeutic applications. Antibiotics have several shortcomings such as cost, continuous use, and harmful effects -- even on the transfected cell population. In addition, selection pressures are often inefficient and fail to provide a population of cells that express the gene of interest (GOI) at high levels. We have used three separate GOI’s to select for solely high-expressing transfectants using targeted toxin selection pressure. Normal Rat Kidney Cells (KNRK) were individually transfected to express green fluorescent protein (GFP), melanopsin or the low-affinity nerve growth factor receptor (p75) using an innovative new transfection delivery vector called pGEI. The results from various assays were utilized to visually determine the expression rate and pattern of the targeted toxin selection method. Melanopsin and p75 -- a photopigment and nerve growth factor, respectively -- were of great interest to express in our transfected cells as a means to study their role in the development and function of neurons. The delivery vector, pGEI, removes resident Galalpha(1-3)Gal epitopes from non- human mammalian cell surfaces. This residue is the target of recombinant Isolectin B4 - Saporin (IB4-SAP), a selective targeted toxin. IB4-SAP is extremely potent, with an EC50 in the low picomolar range for alpha-D-galactopyranoside expressing cells in vitro. The cells with the highest expression of the inserted vector, and therefore the GOI, will have these residues removed. Those that fail to express the vector or do not express the vector in high enough amounts, will not have all the residues removed, and will be targeted and eliminated via IB4-SAP. This method of selection provides a means of purifying the highest- expressing transfected populations using a more cost-effective and time-saving approach.
Related Products: IB4-SAP (Cat. #IT-10)
Araldi D, Bogen O, Green PG, Levine JD (2019) Role of nociceptor toll-like receptor 4 (TLR4) in opioid-induced hyperalgesia and hyperalgesic priming. J Neurosci 39(33):6414-6424. doi: 10.1523/JNEUROSCI.0966-19.2019Objective: To evaluate the hypothesis that hyperalgesia and priming induced by opioids are mediated by similar nociceptor mechanisms.
Summary: Treatment with isolectin B4 (IB4)-saporin or SSP-saporin (which deplete IB4! and peptidergic nociceptors, respectively), or their combination, prevented systemic LDM-induced hyperalgesia, but not priming. HDM-induced priming, but not analgesia, was markedly attenuated in both saporin-treated groups.
Usage: IB4-SAP was diluted in saline and a dose of 3.2 μg in a volume of 20 μl administered intrathecally. SSP-SAP was diluted in saline and a dose of 100 ng in a volume of 20 μl was administered intrathecally.
Related Products: IB4-SAP (Cat. #IT-10), SSP-SAP (Cat. #IT-11)
Pinto LG, Souza GR, Kusuda R, Lopes AH, Sant'Anna MB, Cunha FQ, Ferreira SH, Cunha TM (2019) Non-peptidergic nociceptive neurons are essential for mechanical inflammatory hypersensitivity in mice. Mol Neurobiol 56(8):5715-5728. doi: 10.1007/s12035-019-1494-5
Objective: To determine the role of non-peptidergic nociceptors in mediating mechanical inflammatory hypersensitivity in mice.
Summary: rIB4-SAP oblates non-peptidergic neurons as displayed by the decrease of purinoceptor 3. The depletion of these neurons inhibited the mechanical inflammatory sensitivity induced by GDMF and carrageenan, but not by other expected factors such as nerve growth factor implying the role of this subset of neurons to be one of mediation as opposed to direct nociception.
Usage: IB4-SAP (0.16–3.2 μg/5 μl, i.t.), unconjugated Saporin (as control, 1.8 μg/5 μl, i.t.), or saline (vehicle, 5 μl/i.t.) were injected into the subarachnoid space on the midline between the L5 and L6 vertebrae.
Related Products: IB4-SAP (Cat. #IT-10), Saporin (Cat. #PR-01)
Watanabe S, Sakurai T, Nakamura S, Miyoshi K, Sato M (2018) The combinational use of CRISPR/Cas9 and targeted toxin technology enables efficient isolation of bi-allelic knockout non-human mammalian clones. Int J Mol Sci 19:E1075. doi: 10.3390/ijms19041075Objective: Most genome editing systems employ transient treatment with selective drugs such as puromycin to obtain the desired genome-edited cells, which often allows some untransfected cells to survive and decreases the efficiency of generating genome-edited cells. The authors developed a novel targeted toxin-based drug-free selection system for the enrichment of genome-edited cells.
Summary: Results indicate that a combination of the CRISPR/Cas9 system and targeted toxin technology using IB4-SAP allows efficient enrichment of genome-edited clones, particularly bi-allelic KO clones.
Usage: Cells were trypsinized 3 days after transfection and approximately 80% were incubated for 30 min at 37°C in a solution (25 mcL) containing 0.5–1.0 mcg IB4-SAP (Cat. #IT-10).
Related Products: IB4-SAP (Cat. #IT-10)
Toxins as tools: Fingerprinting neuronal pharmacology.
Israel MR, Morgan M, Tay B, Deuis JR (2018) Toxins as tools: Fingerprinting neuronal pharmacology. Neurosci Lett 679:4-14. doi: 10.1016/j.neulet.2018.02.001Summary: This review article provides an overview of the experimental techniques used to assess the effects that toxins have on neuronal function, as well as discussion on toxins that have been used as tools, with a focus on toxins that target voltagegated and ligand-gated ion channels.
Related Products: IB4-SAP (Cat. #IT-10), NPY-SAP (Cat. #IT-28)
Araldi D, Khomula EV, Ferrari LF, Levine JD (2018) Fentanyl induces rapid onset hyperalgesic priming: Type I at peripheral and type II at central nociceptor terminals. J Neurosci 38(9):2226-2245. doi: 10.1523/JNEUROSCI.3476-17.2018Objective: To evaluate priming, at both nociceptor terminals, the effect of local administration of agents that reverse type I (protein translation) or type II [combination of Src and mitogen-activated protein kinase (MAPK)] priming
Summary: Fentanyl, acting at the -opioid receptor (MOR), induces hyperalgesia and hyperalgesic priming at both the central and peripheral terminal of nociceptors and this is mediated by endoplasmic reticulum Ca2 signaling. Priming in the central terminal is type II, whereas that in the peripheral terminal is type I. Our findings may provide useful information for the design of drugs with improved therapeutic profiles, selectively disrupting individual MOR signaling pathways, to maintain an adequate long-lasting control of pain.
Usage: IB4-SAP was diluted in saline and a dose of 3.2 μg in a volume of 20 μl and administered intrathecally 14 d before experiments
Related Products: IB4-SAP (Cat. #IT-10)
CD44 signaling mediates high molecular weight hyaluronan-induced antihyperalgesia.
Ferrari LF, Khomula EV, Araldi D, Levine JD (2018) CD44 signaling mediates high molecular weight hyaluronan-induced antihyperalgesia. J Neurosci 38(2):308-321. doi: 10.1523/JNEUROSCI.2695-17.2017Objective: To study the role of the cognate hyaluronan receptor, CD44, signaling in anti-hyperalgesia induced by high molecular weight hyaluronan (HMWH).
Summary: These results demonstrate the central role of CD44 signaling in HMWH-induced anti-hyperalgesia, and establish it as a therapeutic target against inflammatory and neuropathic pain.
Usage: Both IB4-SAP and SSP-SAP were diluted in saline to doses previously shown to deplete nonpeptidergic (3.2 mcg/rat for IB4-SAP) and peptidergic (100 ng/rat for SSP-SAP) fibers. The toxins were administered intrathecally, in a volume of 20 mcl, 14 d before intradermal injection of LMWH on the dorsum of the hindpaw. Treatment with either conjugate, or a combination of the two, did not significantly affect mechanical nociceptive threshold.
Related Products: IB4-SAP (Cat. #IT-10), SSP-SAP (Cat. #IT-11)
Mediation of movement-induced breakthrough cancer pain by IB4-binding nociceptors in rats.
Havelin J, Imbert I, Sukhtankar D, Remeniuk B, Pelletier I, Gentry J, Okun A, Tiutan T, Porreca F, King T (2017) Mediation of movement-induced breakthrough cancer pain by IB4-binding nociceptors in rats. J Neurosci 37:5111-5122.. doi: 10.1523/JNEUROSCI.1212-16.2017
Objective: To define a novel preclinical measure of movement-induced breakthrough pain (BTP) that is observed in the presence of morphine controlling ongoing pain.
Summary: Novel compounds targeting IB4-binding nociceptors may improve pain management for cancer pain patients and other patient populations suffering from BTP that is inadequately treated by currently available medications.
Usage: To determine the effect of eliminating input from IB4-binding fibers, separate groups of rats received spinal administration of IB4-SAP or the control, Blank-SAP (3.2 mcg/20 mcl saline) followed by a 10 mcl flush of saline. Movement of an air bubble placed between drug solution and saline was used to monitor progress of the injection.
Related Products: IB4-SAP (Cat. #IT-10), Blank-SAP (Cat. #IT-21)
Gi-protein-coupled 5-HT1B/D receptor agonist sumatriptan induces type I hyperalgesic priming.
Araldi D, Ferrari L, Levine J (2016) Gi-protein-coupled 5-HT1B/D receptor agonist sumatriptan induces type I hyperalgesic priming. Pain 157:1773-1782. doi: 10.1097/j.pain.0000000000000581
Summary: The present study explored the possibility that, like MOR and A1-adenosine receptor agonists, triptans would also induce type II hyperalgesic priming. In addition, they explored the 5-HT receptor subtypes at which triptans act (5-HT1B, 5-HT1D and 5-HT7) to induce priming. They report that while sumatriptan, a prototypical 5-HT1B/D receptor agonist induces hyperalgesic priming, this priming meets the criteria for type I rather than type II priming. Isolectin B4 (IB4)-saporin (Cat. #IT-10), was diluted in saline, and a dose of 3.2 μg, in a volume of 20 μL was administered intrathecally to rats. The neurotoxin [Sar9,Met(O2) 11]-substance P-saporin (SSP-Saporin, Cat. #IT-11) was diluted in saline, and a dose of 100 ng, in a volume of 20 μL was administered intrathecally. In a model of pain chronification, sumatriptan induces both mechanical hyperalgesia at the site of injection and type I hyperalgesic priming, in nociceptors innervating the cutaneous injection site.
Related Products: IB4-SAP (Cat. #IT-10), SSP-SAP (Cat. #IT-11)
Roles of isolectin B4-binding afferents in colorectal mechanical nociception.
La J, Feng B, Kaji K, Schwartz E, Gebhart G (2016) Roles of isolectin B4-binding afferents in colorectal mechanical nociception. Pain 157:348-354. doi: 10.1097/j.pain.0000000000000380
Summary: Primary afferent neurons are often classified as peptidergic or non-peptidergic. One characteristic of the non-peptidergic neurons is that they bind isolectin-B4. In the spinal cord these neurons terminate mainly in inner lamina II. Non-peptidergic neurons in the spinal cord have been found to be involved in various aspects of pain response. In this work the authors examined the role of non-peptidergic neurons in the viscerosensory system. Rats received 1.5 μg of intrathecal recombinant IB4-SAP (Cat. #IT-10) between the L5 and L6 vertebrae. Saporin (Cat. #PR-01) was used as a control. While IHC demonstrated that a majority of viscerosensory L6 colon DRG neurons are IB4+, they do not play a significant role in colorectal mechano-nociception.
Related Products: IB4-SAP (Cat. #IT-10), Saporin (Cat. #PR-01)
A non-inheritable maternal Cas9-based multiple-gene editing system in mice.
Sakurai T, Kamiyoshi A, Kawate H, Mori C, Watanabe S, Tanaka M, Uetake R, Sato M, Shindo T (2016) A non-inheritable maternal Cas9-based multiple-gene editing system in mice. Sci Rep 6:20011. doi: 10.1038/srep20011
Summary: In this work, the authors generated transgenic mice with systemic Cas9 overexpression (Cas9 mice) in order to simplify the procedure of generating genetically modified animals using the CRISPR/Cas9 system – only guide RNAs (gRNAs) would need to be administered to induce mutations at target loci. To test Cas9 mice for genome editing in vitro, the authors transiently transfected primary fibroblasts from Cas9 mice with Ggta1 gRNA (Ggta1 is responsible for synthesizing the cell-surface α-Gal epitope). They treated the fibroblasts with rIB4-SAP (Cat. #IT-10) and found that it killed Ggta1 +/+ and KO/+ cells, while biallelic Ggta1 KO cells survived as they did not synthesize the α-Gal epitope. This indicated that primary cells from the Cas9 transgenic mice have CRISPR/Cas9 genome editing capability with the administration of gRNA alone. The success of their experiments indicate that this method could potentially be used to generate other genetically modified animals.
Related Products: IB4-SAP (Cat. #IT-10)
Kras J, Weisshaar C, Pall P, Winkelstein B (2015) Pain from intra-articular NGF or joint injury in the rat requires contributions from peptidergic joint afferents. Neurosci Lett 604:193-198. doi: 10.1016/j.neulet.2015.07.043
Summary: Both peptidergic and non-peptidergic neurons innervate the facet joint, which is the source of pain in a majority of neck trauma. In this work the authors examined these subpopulations of neurons to determine the contribution of each in facet joint pain. 100 ng of SSP-SAP (Cat. #IT-11) was injected into bilateral C6/C7 facet joints of rats. Alternatively, rats received 5 μg of rIB4-SAP (Cat. #IT-10) via the same method. Saporin (Cat. #PR-01) was used as control. SSP-SAP, but not rIB4-SAP was able to prevent NGF-induced mechanical and thermal hypersensitivity. SSP-SAP administration also prevented behavioral hypersensitivity and NGF upregulation in the dorsal root ganglion after facet joint distraction. The data indicate that interference with peptidergic signaling within the facet joint may be a treatment for pain originating in that location.
Related Products: SSP-SAP (Cat. #IT-11), IB4-SAP (Cat. #IT-10), Saporin (Cat. #PR-01)
Araldi D, Ferrari L, Levine J (2015) Repeated mu-opioid exposure induces a novel form of the hyperalgesic priming model for transition to chronic pain. J Neurosci 35:12502-12517. doi: 10.1523/JNEUROSCI.1673-15.2015
Summary: Repeated administration of mu-opioid receptor agonists can lead to persistent mechanical hyperalgesia. One current hypothesis is that a form of hyperalgesic priming is triggered by the repeated activation of these receptors. Classic hyperalgesic priming is associated with signaling via protein kinase Cε (PKε), which is mediated by isolectin-B4+ (IB4) nociceptors. In this work the authors eliminated the IB4+ nociceptors with a 3.2 μg intrathecal injection of recombinant IB4-SAP (Cat. #IT-10). The authors found that hyperalgesic priming induced through the use of DAMGO was dependent on protein kinase A activation rather than activation of PKε. This work demonstrates a novel model for hyperalgesic priming transitioning to chronic pain.
Related Products: IB4-SAP (Cat. #IT-10)
Saeed A, Pawlowski S, Ribeiro-da-Silva A (2015) Limited changes in spinal lamina I dorsal horn neurons following the cytotoxic ablation of non-peptidergic C-fibers. Mol Pain 11:54. doi: 10.1186/s12990-015-0060-z
Summary: For the most part nociceptive information is moved from the periphery to the spinal cord through small diameter primary afferents. One subclass of these afferents is further divided into peptidergic and non-peptidergic populations. The authors examined the role of the non-peptidergic afferents in normal nociception and pain, especially the aspect that in rat neuropathic and inflammatory pain models there is novel expression of neurokinin-1 receptors in some neurons normally devoid of this protein. Rats received 4.8-μg injections of rIB4-SAP (Cat. #IT-10) into the left sciatic nerve, over three injection sites. While the number of non-peptidergic neurons was significantly reduced, de novo expression of the neurokinin-1 receptor was not increased in lamina I pyramidal projection neurons.
Related Products: IB4-SAP (Cat. #IT-10)
Oyamaguchi A, Abe T, Sugiyo S, Niwa H, Takemura M (2016) Selective elimination of isolectin B4-binding trigeminal neurons enhanced formalin-induced nocifensive behavior in the upper lip of rats and c-Fos expression in the trigeminal subnucleus caudalis. Neurosci Res 103:40-47. doi: 10.1016/j.neures.2015.07.007
Summary: In adult rats non-peptidergic neurons and peptidergic neurons innervate different areas and layers of the lamina. It is thought that these two neuronal populations play different roles in nociceptive processing, but the specific function of each group is not well understood. In order to investigate peptidergic and non-peptidergic neurons in orofacial pain processing the authors injected the cisterna magna of rats with 2.9 μg of rIB4-SAP (Cat. #IT-10). Blank-SAP (Cat. #IT-21) was used as a control. The lesioned animals displayed more frequent face-rubbing responses on the administration of formalin, indicating that IB4-binding neurons in the trigeminal nerve play an anti-nociceptive role in response to this type of pain.
Related Products: IB4-SAP (Cat. #IT-10), Blank-SAP (Cat. #IT-21)
Ono K, Ye Y, Viet C, Dang D, Schmidt B (2015) TRPV1 expression level in isolectin B₄-positive neurons contributes to mouse strain difference in cutaneous thermal nociceptive sensitivity. J Neurophysiol 113:3345-3355. doi: 10.1152/jn.00973.2014
Summary: In order to determine whether IB4-positive trigeminal sensory neurons affect pain sensitivity, the authors administered 2 μg of rIB4-SAP (Cat. #IT-10) to the right infraorbital foramen. Saporin (Cat. #PR-01) was used as a control.
Related Products: IB4-SAP (Cat. #IT-10), Saporin (Cat. #PR-01)
Sato M, Watanabe S (2015) Featured Article: Drug-free selection of stable transfectants using targeted toxin technology and a vector expressing cell-surface carbohydrate-digesting enzyme. Targeting Trends 16(2)
Related Products: IB4-SAP (Cat. #IT-10)
Read the featured article in Targeting Trends.
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αCGRP is essential for algesic exocytotic mobilization of TRPV1 channels in peptidergic nociceptors.
Devesa I, Ferrándiz-Huertas C, Mathivanan S, Wolf C, Luján R, Changeux J, Ferrer-Montiel A (2014) αCGRP is essential for algesic exocytotic mobilization of TRPV1 channels in peptidergic nociceptors. Proc Natl Acad Sci U S A 111:18345-18350. doi: 10.1073/pnas.1420252111
Summary: The sensitization of transient receptor potential vanilloid 1 (TRPV1) can lead to the development and maintenance of chronic pathological pain conditions. In this work the authors determined that TRPV1 receptors use membrane insertion mechanisms in order to potentiate neuronal excitability. In order to specifically link this activity to peptidergic neurons the authors treated rat primary dorsal root ganglion cultures with 10 mM rIB4-SAP (Cat. #IT-10) to deplete the non-peptidergic neurons.
Related Products: IB4-SAP (Cat. #IT-10)
Sato M, Inada E, Saitoh I, Matsumoto Y, Ohtsuka M, Miura H, Nakamura S, Sakurai T, Watanabe S (2015) A combination of targeted toxin technology and the piggyBac-mediated gene transfer system enables efficient isolation of stable transfectants in nonhuman mammalian cells. Biotechnol J 10:143-153. doi: 10.1002/biot.201400283
Summary: In this work the authors developed a new transfection strategy that takes advantage of the fact that many cell lines endogenously express α-1,3-galactosyltransferase (α-Gal), the target of rIB4-SAP (Cat. #IT-10). After transfection low expressing or non-transfected cells are killed by an application of rIB4-SAP at 80 μg/ml for 2 hours. The surviving cells eventually express α-Gal again, and require no selective agent to maintain expression of the gene of interest. These transfected cells can be transfected again using the same method.
Related Products: IB4-SAP (Cat. #IT-10)
Properties of recombinant isolectin B4 (IB4): Binding and immunostaining
Kohls MD, Lappi DA, Ancheta LR (2014) Properties of recombinant isolectin B4 (IB4): Binding and immunostaining. Neuroscience 2014 Abstracts 627.07. Society for Neuroscience, Washington, DC.
Summary: Isolectin B4 (IB4) is a protein found in the seeds of Griffonia simplicifolia, a woody climbing shrub native to western and central Africa. Although initially used as an identifier and agglutination agent for B-type red blood cells, it has since become widely used in the neurosciences as a neuronal tracer, for labeling specific populations in the spinal cord, and as a targeting moiety for delivering toxins to specific cells. Recent developments in response to competition from the nutritional supplement industry have reduced the available supply of seeds from which the native protein is purified. In order to create a consistent supply of pure and active IB4 we have determined the full nucleotide sequence of the IB4 gene, cloned it from Griffonia genomic DNA, and expressed recombinant IB4 in E. coli. The recombinant IB4 (rIB4) was purified and tested in several activity assays against the native protein. A fusion protein of rIB4 and GFP was created to demonstrate the use of this protein in immunostaining. Griffonia also contains isolectin A that agglutinates A-type red blood cells - the A and B lectins form tetramers with varying subunit combinations. These tetramers are potential sources of contamination in preparations of the native protein. rIB4 is completely free of any A lectin contamination. The rIB4 is highly pure, and has identical activity to the native protein.
Related Products: IB4-SAP (Cat. #IT-10)
Role for monocyte chemoattractant protein-1 in the induction of chronic muscle pain in the rat.
Alvarez P, Green P, Levine J (2014) Role for monocyte chemoattractant protein-1 in the induction of chronic muscle pain in the rat. Pain 155:1161-1167. doi: 10.1016/j.pain.2014.03.004
Summary: In order to better understand where monocyte chemoattractant protein 1 (MCP-1) fits in the chronic pain landscape the authors performed a series of experiments using antisense and mismatch oligodeoxynucleotides against the MCP-1 receptor in rats. Some animals also received 3.2 μg intrathecal injections of IB4-SAP (Cat. #IT-10). IB4-SAP treatment removed water avoidance stress-induced muscle hyperalgesia, as well as preventing stress-induced hyperalgesic priming that is a usual response to administration of MCP-1. The data indicate that MCP-1 takes action through its receptors on IB4+ nociceptors.
Related Products: IB4-SAP (Cat. #IT-10)
Sato M, Miyoshi K, Nagao Y, Nishi Y, Ohtsuka M, Nakamura S, Sakurai T, Watanabe S (2014) The combinational use of CRISPR/Cas9-based gene editing and targeted toxin technology enables efficient biallelic knockout of the α-1,3-galactosyltransferase gene in porcine embryonic fibroblasts. Xenotransplantation 21:291-300. doi: 10.1111/xen.12089
Summary: Results indicate that a combination of the CRISPR/Cas9 system and targeted toxin technology using IB4-SAP allows efficient enrichment of genome-edited clones, particularly bi-allelic KO clones.
Usage: Cells were trypsinized 3 days after transfection and approximately 80% were incubated for 30 min at 37°C in a solution (25 mcL) containing 0.5–1.0 mcg IB4-SAP.
Related Products: IB4-SAP (Cat. #IT-10)
Ye Y, Bae S, Viet CT, Troob S, Bernabe D, Schmidt BL (2014) IB4(+) and TRPV1(+) sensory neurons mediate pain but not proliferation in a mouse model of squamous cell carcinoma. Behav Brain Funct 10(1):5. doi: 10.1186/1744-9081-10-5
Objective: To evaluate subtypes of sensory neurons involved in cancer pain and proliferation.
Summary: IB4(+) neurons play an important role in cancer-induced mechanical allodynia, while TRPV1 mediates cancer-induced thermal hyperalgesia. Characterization of the sensory fiber subtypes responsible for cancer pain could lead to the development of targeted therapeutics.
Usage: IB4(+) neurons play an important role in cancer-induced mechanical allodynia, while TRPV1 mediates cancer-induced thermal hyperalgesia. Characterization of the sensory fiber subtypes responsible for cancer pain could lead to the development of targeted therapeutics.
Related Products: IB4-SAP (Cat. #IT-10), Saporin (Cat. #PR-01)
Role of nonpeptidergic subset of primary afferent neurons in inflammatory hypernociception in mice.
Pinto LG, Souza GR, Lopes AHP, Talbot J, Cunha FQ, Cunha TM, Ferreira SH (2013) Role of nonpeptidergic subset of primary afferent neurons in inflammatory hypernociception in mice. Neuroscience 2013 Abstracts 256.15. Society for Neuroscience, San Diego, CA.
Summary: Sensory information is transmitted from the periphery to the spinal cord by distinct subsets of primary afferent neurons, including small diameter unmyelinated C-fibers, which plays an important role in detecting noxious stimuli. C-fiber nociceptors have been divided into two classes, the peptidergic and nonpeptidergic. While many of the differences between peptidergic and nonpeptidergic neurons are now appreciated, a possible functional difference between these two classes of C fibers in the genesis of acute nociception as well as inflammatory pain is still unclear. Thus, this study aims to clarify the role of nonpeptidergic C fibers in acute nociception induced by mechanical, thermal and chemical stimuli as well as in inflammatory hypernociception. In order to elucidate differences between these two classes of C fibers, a neurotoxin was used to selectively eliminate the nonpeptidergic C fibers: a saporin conjugated to isolectin B4 (IB4). Nociceptive threshold was evaluated through thermal (Hargreaves) and mechanical (filaments and electronic von Frey) tests in C57BL/6 mice. Nociception models were induced by intraplantar (i.pl.) injection of capsaicin and formalin (acute nociception) or by i.pl. administration of prostaglandin E2 (PGE2), epinephrine, endothelin, NGF, GDNF and carrageenan (inflammatory hypernociception). P2X3 and TRPV1 expression were analyzed by Western blot of dorsal root ganglion (DRG). The expression of IB4-labeled in spinal cord was determined by immunofluorescense using confocal microcopy. Firstly, it was observed that the intrathecal administration of IB4-saporin did not change baseline thermal and mechanical nociceptive threshold of the mice paw when compared to saline and saporin-control groups. The intrathecal administration of IB4-saporin reduced mechanical inflammatory hypernociception induced by carrageenan, epinephrine, endothelin, PGE2 or GDNF, but not NGF, in mice. Similarly, the treatment with IB4-saporin inhibited the nociception caused by intraplantar injection of the capsaicin. By contrast, the acute nociception induced by formalin did not change by administration of IB4-saporin. In addition, the expression of TRPV1 and P2X3 in DRG were reduced after treatment with IB4-saporin. Consistent with these findings, we found that IB4-saporin injection decreased the expression of IB4-labeled in spinal cord. These results suggest that absence the nonpeptidergic C fibers does not affect basal nociceptive threshold. However, these fibers are essential for the development of nociception in the paw of mice induced by inflammatory stimuli like PGE2, epinephrine, endothelin, carrageenan and capsaicin.
Related Products: IB4-SAP (Cat. #IT-10)
Sato M, Akasaka E, Saitoh I, Ohtsuka M, Nakamura S, Sakurai T, Watanabe S (2013) Targeted toxin-based selectable drug-free enrichment of Mammalian cells with high transgene expression. Biology (Basel) 2:341-355. doi: 10.3390/biology2010341
Summary: Cell transfection is a powerful tool for evaluation of function and expression of newly discovered genes as well as for both small and large scale eukaryotic expression of proteins. Most transfection strategies require a selection agent to eliminate cells that do not internalize the plasmid containing the gene of interest. Subsequent maintenance of the tranfected cells requires the presence of the selection agent, and the expression levels of the gene of interest have to be evaluated on a cell by cell basis. In this work the authors designed a system utilizing 50 μg/ml rIB4-SAP (Cat. #IT-10) to eliminate non-transfected cells and select for strong expression of the gene of interest. The data demonstrate that this technique will generate stable transfected cells that express the gene of interest at high levels.
Related Products: IB4-SAP (Cat. #IT-10)
IB4 (+) neurons contribute to force-induced cancer pain but not cancer proliferation
Ye Y, Viet CT, Dang D, Schmidt BL (2012) IB4 (+) neurons contribute to force-induced cancer pain but not cancer proliferation. Neuroscience 2012 Abstracts 67.10. Society for Neuroscience, New Orleans, LA.
Summary: The primary treatment for cancer pain is μ-opiates; however, often μ-opiates are not effective and they produce multiple debilitating side effects. Recent studies show that μ- and δ-opioid receptors are separately expressed on IB4 (-) and IB4 (+) neurons, which mediate thermal and mechanical pain, respectively. We investigated the contribution of IB4 (+) and IB4 (-) neurons to cancer-induced mechanical and thermal hypersensitivity and investigated the role of these fibers to cancer proliferation. We used two separate mouse cancer pain models: 1) a cancer supernatant injection model, and 2) an orthotopic cancer model. The former model isolated the effect of the cancer secretome while the latter examined the effect of the following constituents within the cancer microenvironment: the cancer, the cancer secretome and the host tissue. Using the cancer supernatant model, along with injection of a selective δ-opioid receptor agonist and a P2X3 antagonist to target IB4 (+) neurons, we showed that IB4 (+) neurons played arole in cancer-supernatant-induced mechanical allodynia, but not thermal hyperalgesia. Selective ablation of IB4 (+) neurons in the spinal cord using IB4-saporin affected cancer-supernatant-induced mechanical but not thermal hypersensitivity. In the orthotopic cancer model, mice with paw cancer exhibited both mechanical and thermal hypersensitivity. Selective ablation of IB4(+) neurons decreased mechanical hypersensitivity; however thermal hypersensitivity was increased. We hypothesized that increased thermal hyperalgesia was associated with a compensatory elevation of TRPV1 expression in the spinal cord. Thermal latency in the mouse cancer paw was increased by intrathecal TRPV1 antagonist and selective removal of TRPV1 terminals by capsaicin in the IB4-saporin treated mice compared to saporin treated mice. Mechanical threshold was not affected by either the TRPV1 antagonist or capsaicin treatment. In the spinal cord, TRPV1 protein levels were increased in cancer mice compared to naïve mice, and TRPV1 was likely to be increased in the IB4-saporin treated cancer mice compared to saporin treated cancer mice. We investigated cancer proliferation by measuring tumor volume. Tumor volume was not affected by selective ablation of IB4 (+) neurons. Our findings suggest that peripherally administered pharmacological agents targeting IB4 (+) neurons, such as a selective δ-opioid receptor agonist or P2X3 antagonist, might be effective for treating cancer pain in patients. Acknowledgements: Supported by NIH/NIDCR R21 DE018561
Related Products: IB4-SAP (Cat. #IT-10)
IB4(+) nociceptors mediate persistent muscle pain induced by GDNF.
Alvarez P, Chen X, Bogen O, Green PG, Levine JD (2012) IB4(+) nociceptors mediate persistent muscle pain induced by GDNF. J Neurophysiol 108(9):2545-2553. doi: 10.1152/jn.00576.2012
Summary: GDNF is found in skeletal muscle and can trigger mechanical hyperalgesia. The authors administered a 3.2-μg intrathecal dose of IB4-SAP (Cat. #IT-10) to rats. Loss of the IB4(+) nociceptors led to decreased hyperalgesic priming as well as a reduction in GDNF-induced hyperalgesia. These data indicate that GDNF plays a role in mediating induction of pain.
Related Products: IB4-SAP (Cat. #IT-10)
Taylor AM, Osikowicz M, Ribeiro-da-Silva A (2012) Consequences of the ablation of nonpeptidergic afferents in an animal model of trigeminal neuropathic pain. Pain 153(6):1311-1319. doi: 10.1016/j.pain.2012.03.023
Summary: The authors used IB4-SAP (Cat. #IT-10; 3.2 μg injected into the mental nerve) to eliminate C-fibers in the lower lip of rats to see if this was enough to induce the sprouting of autonomic fibers. Saporin alone (Cat. #PR-01) was used as a control. Only parasympathetic fibers sprouted in these animals, but after nerve ligation surgery both sympathetic and parasympathetic fibers sprouted.
Related Products: IB4-SAP (Cat. #IT-10), Saporin (Cat. #PR-01)
Analgesia targeting IB4-positive neurons in cancer-induced mechanical hypersensitivity.
Ye Y, Dang D, Viet CT, Dolan JC, Schmidt BL (2012) Analgesia targeting IB4-positive neurons in cancer-induced mechanical hypersensitivity. J Pain 13(6):524-531. doi: 10.1016/j.jpain.2012.01.006
Summary: DOR (δ opioid receptor) agonists produce minimal side effects and do not lead to tolerance, making them potential alternatives to the widely used μ opioid receptor agonists. Utilizing the fact that DOR's are expressed by IB4-positive neurons, the authors injected the subarachnoid space between the L4 and L5 vertebrae of rats with 2.4 μg of IB4-SAP (Cat. #IT-10). 3 μg of saporin (Cat. #PR-01) was used as a control. The results indicate that pharmacological agents targeting IB4-positive neurons may have use in cancer pain treatment.
Related Products: IB4-SAP (Cat. #IT-10), Saporin (Cat. #PR-01)
IB4-saporin attenuates acute and eliminates chronic muscle pain in the rat.
Alvarez P, Gear RW, Green PG, Levine JD (2012) IB4-saporin attenuates acute and eliminates chronic muscle pain in the rat. Exp Neurol 233(2):859-865. doi: 10.1016/j.expneurol.2011.12.019
Summary: In order to clarify the roles of isolectin B4-positive and IB4-negative nociceptors in inflammatory and ergonomic muscle pain, the authors administered 3.2 µg of IB4-SAP (Cat. #IT-10) into the intrathecal space of rats. Although the baseline mechanical nociceptive threshold was not affected in the lesioned animals, mechanical hyperalgesia had a shorter duration. In the ergonomic models peak hyperalgesia was attenuated, and prolongation of PGE2-induced mechanical hyperalgesia was completely prevented.
Related Products: IB4-SAP (Cat. #IT-10)
Saeed AW, Ribeiro-Da-Silva A (2011) Consequences of the ablation of non-peptidergic nociceptive fibers on neurokinin-1 receptor expression by spinal lamina I neurons. Neuroscience 2011 Abstracts 804.21. Society for Neuroscience, Washington, DC.
Summary: Spinal dorsal horn lamina I projection neurons expressing the neurokinin-1 receptor (NK-1r) are important in relaying pain-related information from the periphery to the brain. These lamina I neurons have been classified, based on their morphological and physiological properties, into three types: fusiform, multipolar and pyramidal. Of these cell types, pyramidal neurons seldom express the NK-1r and are non-nociceptive. Previously, our laboratory has demonstrated in a cuff model of chronic constriction injury a de novo expression of NK-1r by pyramidal neurons, starting at the same time as the mechanical allodynia. We have also observed a similar de novo expression of NK-1r by pyramidal neurons in an animal model of arthritis. In the current study, we investigated whether the cytotoxic ablation of the non-peptidergic, isolectin B4 (IB4)-binding subpopulation of nociceptive primary afferents led to changes in NK-1r expression by the different lamina I cell types. We injected IB4 conjugated to saporin (SAP) into the left sciatic nerve of anesthetized male Sprague Dawley rats to specifically lesion IB4-positive non-peptidergic nociceptive C-fibers. Cholera toxin subunit B (CTB) was injected into the parabrachial nucleus to label lamina I projection neurons. Animals were tested for thermal and mechanical sensitivity and sacrificed from 2 weeks to 2 months post-lesion. We cut horizontal sections of spinal segments L4 and L5 and processed the tissue for IB4 binding and NK-1r and CTB immunoreactivities using immunofluorescence. IB4-SAP treated animals showed no behavioral changes compared to sham animals when tested for thermal (Hargreaves test), mechanical allodynia (von Frey test) or mechanical hyperalgesia (pin prick test) at any of the time points studied. Compared to the contralateral side and the sham group, lamina I projection neurons in the IB4-SAP treated group revealed an ipsilateral increase in the expression of NK-1r by the fusiform and multipolar neuronal populations. Nonetheless, there was no significant change in the percentage of pyramidal neurons which expressed NK-1r, which remained very low on the ipsilateral side of the IB4-SAP treated group. From these results, we infer that a loss of non-peptidergic afferents does not induce a phenotypic switch in the pyramidal neurons. However, the increase in NK-1r immunoreactivity in lamina I fusiform and multipolar neurons suggests that these cell populations may be important in maintaining the nociceptive responses in the absence of the IB4-positive non-peptidergic afferents. Finally, we suggest that a chronic pain state may be required for the de novo expression of NK-1r by pyramidal neurons.
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Mu and delta opioid receptors on nociceptors attenuate mechanical hyperalgesia in rat.
Joseph EK, Levine JD (2010) Mu and delta opioid receptors on nociceptors attenuate mechanical hyperalgesia in rat. Neuroscience 171(1):344-350. doi: 10.1016/j.neuroscience.2010.08.035
Summary: In this work the authors analyzed nociceptor populations mediating mechanical hyperalgesia in the rat. Rats received 3.2 µg of IB4-SAP (Cat. #IT-10) into the subarachnoid space between the L4 and L5 vertebrae. Hyperalgesia due to the administration of NGF was inhibited by DAMGO and SNC even in lesioned animals. These data indicate that most nociceptor populations are involved in mechanical hyperalgesia, and that the mu opioid and delta opioid receptors are co-expressed on some TrkA-positive nociceptors.
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Hyperalgesic priming is restricted to isolectin B4-positive nociceptors.
Joseph EK, Levine JD (2010) Hyperalgesic priming is restricted to isolectin B4-positive nociceptors. Neuroscience 169(1):431-435. doi: 10.1016/j.neuroscience.2010.04.082
Summary: Hyperalgesic priming is an injury that induces a chronic pain state marked by the presence of inflammatory cytokines. The authors evaluated which populations of nociceptors are involved in the priming process. Rats that received 3.2 µg intrathecal injections of IB4-SAP (Cat. #IT-10) failed to establish priming. Acute mechanical hyperalgesia could still be induced, indicating that IB4+ nociceptors are necessary for priming, but a different nociceptor group is involved with nociceptor sensitization.
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Akasaka E, Watanabe S, Himaki T, Ohtsuka M, Yoshida M, Miyoshi K, Sato M (2010) Enrichment of xenograft-competent genetically modified pig cells using a targeted toxin, isolectin BS-I-B4 conjugate. Xenotransplantation 17:81-89. doi: 10.1111/j.1399-3089.2010.00568.x
Summary: Genetically modified pigs lacking the gala1-3gal epitope may be suitable for production of organs that could be transplanted to humans. The ability to select for a homozygous population of donor somatic cells would accelerate the process of generating these animals, which would otherwise take approximately 2 years. The authors incubated a heterozygous population of 107 porcine embryonic fibroblasts with 1.6 µg of IB4-SAP (Cat. #IT-10). Even after 6 months the treated cells were negative for the agal epitope.
Related Products: IB4-SAP (Cat. #IT-10)
Bogen O, Dina OA, Gear RW, Levine JD (2009) Dependence of monocyte chemoattractant protein 1 induced hyperalgesia on the isolectin B4-binding protein versican. Neuroscience 159:780-786. doi: 10.1016/j.neuroscience.2008.12.049
Summary: Monocyte chemoattractant protein 1 (MCP-1) is involved in generation of inflammatory and neuropathic pain, but the mechanisms underlying this involvement are not understood. Rats received 3.2 µg intrathecal injections of IB4-SAP (Cat. #IT-10). Ten days later the rats received intradermal MCP-1. Animals treated with IB4-SAP did not exhibit the mechanical hyperalgesia normally seen when treated with MCP-1.
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Bogen O, Joseph EK, Chen X, Levine JD (2008) GDNF hyperalgesia is mediated by PLCgamma, MAPK/ERK, PI3K, CDK5 and Src family kinase signaling and dependent on the IB4-binding protein versican. Eur J Neurosci 28:12-19. doi: 10.1111/j.1460-9568.2008.06308.x
Summary: C-fiber nociceptors have been divided into NGF and GDNF classes. Here the authors examined the function of an isolectin B4-binding subpopulation of these nocicepetors. Rats received 40 ng of IB4-SAP (Cat. #IT-10) into the intrathecal space between the fifth and sixth lumbar vertebrae. The results demonstrate that GDNF sensitizes IB4+ C-fiber nociceptors and causes mechanical hyperalgesia.
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IB4 afferent sprouting contributes to bladder dysfunction in spinal rats.
Zinck ND, Downie JW (2008) IB4 afferent sprouting contributes to bladder dysfunction in spinal rats. Exp Neurol 213:293-302. doi: 10.1016/j.expneurol.2008.06.006
Summary: Spinal cord injury can cause inefficient bladder function, but the direct cause is not well understood. Most work has focused on afferent neurons that contain CGRP and respond to NGF. Here the authors investigate the role of isolectin B4 (IB4)-expressing neurons that are supported by GDNF. Rats received intrathecal injections of either 2.4 µg IB4-SAP (Cat. #IT-10) or 3 µg control saporin (Cat. #PR-01). The data suggest that IB4-afferent sprouting is involved in bladder dysfunction following spinal cord transection.
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Joseph EK, Chen X, Bogen O, Levine JD (2008) Oxaliplatin acts on IB4-positive nociceptors to induce an oxidative stress-dependent acute painful peripheral neuropathy. J Pain 9:463-472. doi: 10.1016/j.jpain.2008.01.335
Summary: Oxaliplatin is a platinum-based chemotherapy agent. Use of this reagent produces various pathological pain states, depending on the dosage site. The authors administered 3.2-µg intrathecal injections of IB4-SAP (Cat. #IT-10), using saporin (Cat. #PR-01) as a control. Lesioning IB4-binding neurons in the dorsal horn completely prevented oxaliplatin-induced hyperalgesia, indicating that the IB4-positive nociceptor neuronal subset is crucial to this type of neuropathy.
Related Products: Saporin (Cat. #PR-01), IB4-SAP (Cat. #IT-10)
Saeed AW, Ribeiro-Da-Silva A (2007) Changes in neurokinin-1 receptor expression in populations of spinal lamina I neurons in rats lacking non-peptidergic nociceptive fibers. Neuroscience 2007 Abstracts 821.4/FF19. Society for Neuroscience, San Diego, CA.
Summary: Neurokinin-1 receptor (NK-1r)-containing lamina I projection neurons are deeply involved in the transmission of pain-related information to the brain. Previous studies have shown that lamina I neurons can be classified morphologically into fusiform, pyramidal and multipolar cells, and that these types differ in functional properties, with the pyramidal type being non-nociceptive. Our laboratory has shown not only a considerable increase in immunoreactivity for the NK-1r in animals with CFA-induced arthritis but also a de novo expression of these receptors by pyramidal neurons (Almarestani et al., Soc.Neurosci.Abstr., Program # 249.11, 2006). Based on this, we deemed it interesting to study whether pyramidal neurons would also express NK-1r in an animal model in which we have previously shown a drastic increase in NK-1r expression but no augmented nociceptive responses. To achieve this, we injected, under anesthesia, saporin (SAP) conjugated to the lectin IB4 into the left sciatic nerve of male Sprague Dawley rats to selectively lesion the non-peptidergic nociceptive C-fibers. Animals were sacrificed from 2 weeks to 2 months post-lesion. Horizontal sections of spinal segments L5 and L6 were cut and processed for IB4 binding and NK-1r immunoreactivity using immunofluorescence. Examination of IB4-SAP treated rats at several time points post-lesion revealed increased expression of NK-1r by lamina I cells of the fusiform and multipolar types on the side ipsilateral to the lesion, compared to the contralateral side and to controls. However, pyramidal cells seldom expressed the NK-1r in both control and lesioned animals. Surprisingly, we also observed a direct innervation of lamina I neurons by IB4-positive neurons in control animals, which did not occur ipsilaterally in lesioned animals. These observations support the concept that increased activity by the peptidergic nociceptive afferents may be important in the maintenance of nociceptive responses in the absence of non-peptidergic fibers.
Related Products: IB4-SAP (Cat. #IT-10)
Bailey AL, Bennett G, Ribeiro-da-Silva A (2005) Selective ablation of non-peptidergic C-fibers using IB4-saporin as a tool to identify the functional role of these fibers in pain transmission. Neuroscience 2005 Abstracts 169.14. Society for Neuroscience, Washington, DC.
Summary: Non-peptidergic primary sensory afferents represent a sub-population of unmyelinated C-fibres implicated in the transmission of pain-related information. Evidence indicates that these afferents play a role in pain transmission distinct from peptidergic afferents. However, their exact function in pain signalling is unknown. Investigating alterations in pain behaviours and changes in neurotransmitter and receptor expression in the absence of these sensory afferents may provide some insight into their relative importance in acute and chronic pain conditions. We therefore examined the functional consequences of the selective ablation of non-peptidergic fibres in numerous models of acute pain using Isolectin B4 conjugated to saporin (IB4-SAP). Unilateral injection of IB4-SAP into the sciatic nerve resulted in the selective ablation of IB4-positive neurons in the ipsilateral dorsal root ganglion (DRG). Examination of the central terminals of non-peptidergic primary afferents in the dorsal horn revealed the near complete loss of IB4-positive, P2X3 immunoreactive (IR) varicosities. Moreover, there were marked decreases in TRPV1-IR and substance P (SP-IR) with no change in calcitonin-gene-related peptide (CGRP). Examination of a marker of inhibitory interneurons revealed no changes in GAD-IR. Behavioural analysis showed that IB4-SAP treatment had no effect on acute thermal sensitivity, acute mechanical or cold sensitivity. In an animal model of acute inflammation, IB4-SAP treatment had no effect on inflammatory heat hyperalgesia or mechanical allodynia. However, animals treated with IB4-SAP showed attenuated heat hyperalgesia induced by capsaicin 30 and 60 minutes post-injection. Data relative to acute nociceptive thresholds after other chemical stimuli will be presented. These data indicate that non-peptidergic fibres are minimally involved in acute and inflammatory pain, and may play a more prominent role in high threshold thermal sensation.
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Role of IB4-containing afferents in the effect of IT clonidine
Li X, Bynum T, Hayashida K, Eisenach JC (2005) Role of IB4-containing afferents in the effect of IT clonidine. Neuroscience 2005 Abstracts 171.22. Society for Neuroscience, Washington, DC.
Summary: Alpha2 adrenoceptors diminish pain transmission in animals with normal condition. Our previous data demonstrated clonidine, an Alpha2 adrenoceptor agonist, inhibited calcium influx after an electrical stimulation in the acutely cultured DRG cells from normal animal, 80% of which are Isolectin B4 (IB4) positive. Therefore we assume intrathecal clonidine produces antinociception primarily by actions on IB4-expressing afferents, and clonidine effect will be decreased with the loss of IB4 containing afferents. In the current report, normal rats received an intra-nerve injection of 2 μg of saporin conjugated IB4 (Sap-IB4), a targeted cytotoxin to IB4-expressing neurons, or a 6 μg of saporin as the control in the rat sciatic nerve. Effects of 30 μg intrathecal clonidine were observed for antinociception to thermal and mechanical stimuli in both ipsi- and contra- lateral side to the injection weekly, before and after Sap-IB4 injection for three weeks. Immunocitochemistry study demonstrated that three weeks of Sap-IB4 treatment dramatically decreased IB4 expression in DRG cells or spinal afferent fibers in the ipslateral side. The basal thermal withdrawal latency and mechanical withdrawal threshold were slightly increased by Sap-IB4 in the ipsilateral side one week after injection, which were returned to normal three weeks later. Additionally, the effeccy of 30 μg clonidine for antinociception to thermal and mechanical stimuli was significantly decreased at the end of treatment. These observations suggested IB4 containing afferents may play a very important role in intrathecal clonidine mediated antinociception.
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Molecular neurosurgery with targeted toxins
Wiley RG, Lappi DA (2005) Molecular neurosurgery with targeted toxins. Humana Press, Totowa, New Jersey.
Summary: The idea behind the book was to provide a road map for the users of Molecular Neurosurgery to see how experienced scientists used these exceptional reagents in their work. Experiments with several targeted toxins are described, and readers can get an idea either specifically about a targeted toxin that they’re using, or about how a type of molecule is used and at what dosage, in a paradigm similar to theirs.
Related Products: 192-IgG-SAP (Cat. #IT-01), ME20.4-SAP (Cat. #IT-15), Anti-DBH-SAP (Cat. #IT-03), SSP-SAP (Cat. #IT-11), Dermorphin-SAP / MOR-SAP (Cat. #IT-12), IB4-SAP (Cat. #IT-10), CTB-SAP (Cat. #IT-14)
Featured Article: IB4-SAP prevents axotomy-induced sprouting of Aß fibers
Pearson M (2005) Featured Article: IB4-SAP prevents axotomy-induced sprouting of Aß fibers. Targeting Trends 6(1)
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Read the featured article in Targeting Trends.
See Also:
Tarpley JW, Kohler MG, Martin WJ (2004) The behavioral and neuroanatomical effects of IB(4)-saporin treatment in rat models of nociceptive and neuropathic pain. Brain Res 1029(1):65-76. doi: 10.1016/j.brainres.2004.09.027
Summary: Using the fact that primary afferent neurons bind isolectin B4 (IB4), the authors injected 5 µg of IB4-SAP (Cat. #IT-10) into the sciatic nerve in the left thigh. After recovery, these animals were then treated with a L5 spinal nerve ligation. Lesioned animals displayed attenuated NGF-induced hyperalgesia, as well as differences in other pain-model markers. The data indicate that IB4-positive C-fibers play a discrete role in NGF-induced hyperalgesia, as well as in the development of neuropathic pain.
Related Products: IB4-SAP (Cat. #IT-10)
IB4-SAP reduces IB4 staining in the spinal cord and prevents axotomy induced sprouting of Aβ fibers
Pearson MS, Woods M, Whiteside GT, Garrison AE, Pomonis JD, Walker K (2004) IB4-SAP reduces IB4 staining in the spinal cord and prevents axotomy induced sprouting of Aβ fibers. Neuroscience 2004 Abstracts 858.6. Society for Neuroscience, San Diego, CA.
Summary: Peripheral nerve injury results in hyperalgesia and allodynia. It has been proposed that sprouting of myelinated touch responsive Aß-fibers into the innervation territory of pain sensitive C-fibers in the spinal cord contributes to these abnormal behaviors. The extent of sprouting has recently been challenged and it has been proposed that C-fibers rather than Aß-fibers are involved. We have investigated whether selectively ablating a population of small diameter nociceptors using isolectin B4 conjugated to saporin (IB4-SAP), reduces axotomy-induced sprouting. Male Sprague-Dawley rats received intraneural injections of either IB4-SAP or PBS (3 µl, 0.66 µg/µl) and two weeks later the sciatic nerve was axotomized at the mid-thigh level. Two weeks later, the sciatic nerve was injected with the retrograde tracer, cholera toxin-ß subunit (CTB) (2 µl, 2%) that selectively traces Aß-fibers. Three days post CTB the animals were perfused, the spinal cord harvested, sectioned and stained immunohistochemically for IB4 and CTB. IB4-SAP treatment resulted in a substantial reduction of IB4 staining in the spinal cord versus PBS injected controls. As previously described, axotomy resulted in considerable CTB immunostaining in laminae I, II and III compared to non-axotomized controls in which it was present only in laminae I and III. IB4-SAP treatment followed by axotomy resulted in a substantial reduction of CTB immunostaining in lamina II compared to PBS injected controls. These results suggest that intraneural IB4-SAP ablates a population of small diameter nociceptors and that axotomy induced CTB staining in lamina II is due to uptake of CTB by C-fibers.
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ATS Poster of the Year Winner. Read the featured article in Targeting Trends.
Bailey AL, Bennett G, Ribeiro-da-Silva A (2004) Investigation of the functional role of non-peptidergic primary afferent sensory fibres in the transmission of pain related information. Neuroscience 2004 Abstracts 484.1. Society for Neuroscience, San Diego, CA.
Summary: It is well established that small diameter, unmyelinated, primary afferent C-fibres can be divided into two neurochemically defined populations, one that contains neuropeptides such as Substance P (SP) and Calcitonin-gene related peptide (CGRP) and the other which binds Isolectin B4 (IB4) and is relatively peptide negative. A great deal of circumstantial evidence indicates that the non-peptidergic afferents play a functionally distinct role in pain transmission compared to peptidergic afferents. Indeed, the concept of two distinct subpopulations of C-fibres would indicate the occurrence of parallel processing in pain pathways. However, the functional role of non-peptidergic afferents in the transmission of pain-related information is still unclear. In an attempt to clarify their functional role, we decided to study the development of hyperalgesia and allodynia in adult male Sprague-Dawley rats with selective ablation of IB4-binding, non-peptidergic afferent input to the dorsal horn. To achieve this, we injected IB4 conjugated to Saporin (SAP) into the left sciatic nerve and examined both neurochemical and behavioural changes over a month’s time. Our data show that following injection of the toxin conjugate, IB4-labelling, P2X3-immunopositive fibre terminals disappear from a band in the superficial dorsal horn that expands over a two week period until it comprises most of the mediolateral extent of the dorsal horn. Behavioural data indicates that there are transient changes in acute pain thresholds to mechanical and thermal stimuli. Changes in pain thresholds in animals lacking non-peptidergic input into the spinal dorsal horn in an animal model of Complete Freund’s Adjuvant (CFA) induced inflammation will also be presented.
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Featured Article: Effects of IB4-SAP on bladder overactivity
Yoshimura N (2004) Featured Article: Effects of IB4-SAP on bladder overactivity. Targeting Trends 5(4)
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Read the featured article in Targeting Trends.
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Nishiguchi J, Sasaki K, Seki S, Chancellor MB, Erickson KA, de Groat WC, Kumon H, Yoshimura N (2004) Effects of isolectin B4-conjugated saporin, a targeting cytotoxin, on bladder overactivity induced by bladder irritation. Eur J Neurosci 20(2):474-482. doi: 10.1111/j.1460-9568.2004.03508.x
Summary: It has been demonstrated that IB4-binding non-peptidergic C-fiber neuronal populations are present in afferent pathways to the bladder. The authors used intrathecal administration of 8 µl of 2.5 µM IB4-SAP (Cat. #IT-10) to investigate what roles these neurons play in bladder function. Treated animals displayed a reduction of IB4 afferent nerve terminal staining, as well as a suppression of bladder overactivity due to bladder irritation, without a change in normal bladder function.
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Macrophage-derived tumor necrosis factor alpha, an early developmental signal for motoneuron death.
Sedel F, Béchade C, Vyas S, Triller A (2004) Macrophage-derived tumor necrosis factor alpha, an early developmental signal for motoneuron death. J Neurosci 24(9):2236-2246. doi: 10.1523/JNEUROSCI.4464-03.2004
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Wiley RG, Lappi DA (2003) Targeted toxins in pain. Adv Drug Deliv Rev 55(8):1043-1054. doi: 10.1016/s0169-409x(03)00102-9
Summary: The authors discuss the use of 'molecular neurosurgery' in the study of nociception. Applications using targeted toxins, which include immunotoxins, protein-toxin conjugates, or peptide-toxin conjugates, are illustrated. The authors describe the use of these molecules as research tools, as well as their potential for therapeutics. A helpful table is included that lists neuronal surface markers and class of cells targeted for each targeted toxin. Reagents discussed: CTB-SAP (Cat. #IT-14), IB4-SAP (Cat. #IT-10), OX7-SAP (Cat. #IT-02), 192-Saporin (Cat. #IT-01), ME20.4-SAP (Cat. #IT-15), Anti-DBH-SAP (Cat. #IT-03), Anti-DAT-SAP (Cat. #IT-25), SP-SAP (Cat. #IT-07), Dermorphin-SAP (Cat. #IT-12), Orexin-SAP (Cat. #IT-20), CRF-SAP (Cat. #IT-13), and acetylated LDL-SAP (Cat. #IT-08).
Related Products: CTB-SAP (Cat. #IT-14), IB4-SAP (Cat. #IT-10), OX7-SAP (Cat. #IT-02), 192-IgG-SAP (Cat. #IT-01), ME20.4-SAP (Cat. #IT-15), Anti-DBH-SAP (Cat. #IT-03), Anti-DAT-SAP (Cat. #IT-25), SP-SAP (Cat. #IT-07), Dermorphin-SAP / MOR-SAP (Cat. #IT-12), Orexin-B-SAP (Cat. #IT-20), CRF-SAP (Cat. #IT-13), Acetylated LDL-SAP (Cat. #IT-08)
Nakatsuka T, Tsuzuki K, Ling JX, Sonobe H, Gu JG (2003) Distinct roles of P2X receptors in modulating glutamate release at different primary sensory synapses in rat spinal cord. J Neurophysiol 89(6):3243-3252. doi: 10.1152/jn.01172.2002
Summary: P2X receptors are important modulating neurons in the spinal cord. These authors used IB4-SAP (Cat. #IT-10) to target a neuronal subset, those neurons expressing P2X3 receptors. 2 µg of IB4-SAP were injected directly into the sciatic nerve on one side. Histological examination showed efficient removal of IB4 and P2X3-staining ipsilaterally in the dorsal horn outer laminae. Behavioral experiments showed intact modulation of glutamate release in the absence of P2X3-positive neurons, indicating involvement by other P2X neurons.
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Featured Article: Biotinylated targeting: A viable option?
Lappi DA (2003) Featured Article: Biotinylated targeting: A viable option?. Targeting Trends 4(2)
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Arunkumar R, Ackerman LL, Jones III R, Holdsworth R, Proudfit HK, Hammond DL (2002) Loss of IB4 staining in dorsal root ganglion neurons after spinal nerve ligation is not the result of cell death. IASP 2002 Abstracts International Association for the Study of Pain, San Diego, CA.
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Loss of IB4-positive sensory neurons mitigates the consequences of nerve injury in the rat.
Tarpley JW, MacIntyre E, Martin WJ (2002) Loss of IB4-positive sensory neurons mitigates the consequences of nerve injury in the rat. IASP 2002 Abstracts International Association for the Study of Pain, San Diego, CA.
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Cytotoxic targeting of isolectin IB4-binding sensory neurons.
Vulchanova L, Olson TH, Stone LS, Riedl MS, Elde R, Honda CN (2001) Cytotoxic targeting of isolectin IB4-binding sensory neurons. Neuroscience 108(1):143-155. doi: 10.1016/s0306-4522(01)00377-3
Summary: Vulchanova et al. examine the role of IB4-binding neurons in nociception. IB4-SAP (Cat. #IT-10) was injected into rats (2 µg in left sciatic nerve). The resulting ablation of IB4-binding neurons provides evidence for their role in nociceptive processing and demonstrates a rapid compensatory response to signalling of acute pain.
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Nakatsuka T, Takeda D, Gu JG (2001) α,β-methylene ATP sensitive P2X receptor mediated enhancement of glutamate release from the central terminals of Aδ primary afferents onto lamina V neurons in rat spinal cord. Neuroscience 2001 Abstracts 158.16. Society for Neuroscience, San Diego, CA.
Summary: We examined the role of αβmATP-sensitive P2X receptors in modulating glutamate release from sensory synapses of the spinal cord by using whole-cell patch-clamp recordings from dorsal horn neurons in lamina V region. The majority of lamina V neurons synapsed with terminals expressing αβmATP-sensitive P2X receptors. Application of P2X receptor agonist 100 μM αβmATP resulted in a large increase in mEPSC frequency. The increases in mEPSC frequency by αβmATP were completely abolished by the P2X receptor antagonist 10 μM PPADS, but were not blocked by Ca2+ channel blocker 30 μM La3+. αβmATP remained to be effective in increasing mEPSC frequency after the removal of superficial dorsal horn (lamina I-III) or after the injection of IB4-saporin into sciatic nerve to remove P2X3 expressing afferent terminals. Furthermore, we found that αβmATP-sensitive synapses of lamina V neurons were associated with central terminals derived from Aδ primary afferents. The EPSCs evoked by dorsal root stimulation at Aδ-fiber intensity were potentiated by 1 μM αβmATP as well as by the ecto-ATPase inhibitor 10 μM ARL67156, and depressed in the presence of 10 μM PPADS and 5 μM suramin. These results suggest that αβmATP-sensitive P2X receptors play a significant role in modulating excitatory synaptic transmission in the spinal cord.
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Capsaicin-sensitive inhibitory pathway in rat spinal cord dorsal horn.
Gu JG, Nakatsuka T, Tanaka E, Takeda D, Jennifer LX (2001) Capsaicin-sensitive inhibitory pathway in rat spinal cord dorsal horn. Neuroscience 2001 Abstracts 158.13. Society for Neuroscience, San Diego, CA.
Summary: The inhibitory system in the spinal cord plays an important role in regulating nociceptive sensory inputs. Here we examined inhibitory synaptic activity in lamina V neurons of the spinal dorsal horn following the activation of capsaicin VR1 receptors. Experiments were performed with spinal cord slice preparations and inhibitory postsynaptic currents (IPSCs) were recorded using patch-clamp technique. Bath application of capsaicin (2 μM) increased the amplitude and frequency of GABAergic and glycinergic spontaneous IPSCs in the majority of lamina V neurons tested. The effects of capsaicin were completely antagonized by capsazepine (10 μM), and were also blocked in the presence of tetrodotoxin (0.5 μM). However, when CNQX (20 μM) and APV (100 μM) were used to block glutamatergic synaptic transmission, the effects of capsaicin were not abolished. Furthermore, after the injection of IB4-saporin into sciatic nerve to remove IB4-positive C-primary afferent terminals, capsaicin still increased sIPSC frequency in the presence of CNQX and APV. These results suggest that inhibitory pathway could be recruited in the absence of glutamatergic inputs from primary afferents. The release of neuropeptides from capsaicin-sensitive C-primary afferents may activate GABAergic and glycinergic interneurons in superficial laminae, and the inhibitory activity may be further forwarded to lamina V neurons. The capsaicin-sensitive inhibitory pathway may play an important role in the control of nociceptive transmission in the spinal cord.
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Contribution of IB4-positive sensory neurons to NGF-induced hyperalgesia in the rat.
Tarpley JW, Martin WJ, Baldwin BS, Forrest MJ, MacIntyre DE (2000) Contribution of IB4-positive sensory neurons to NGF-induced hyperalgesia in the rat. Neuroscience 2000 Abstracts 633.18. Society for Neuroscience, New Orleans, LA.
Summary: Sensory information is transmitted from the periphery to the spinal cord by distinct subsets of primary afferent neurons, including two major classes of C-fibers that are distinguished by their ability to bind the lectin IB4. IB4-positive neurons are primarily non-peptidergic, express the receptor tyrosine kinase, Ret, and are preferentially sensitive to the neurotrophic factor, GDNF. By contrast, the nerve growth factor (NGF) receptor tyrosine kinase, trkA, is predominantly expressed in IB4-negative neurons that contain substance P. Previous work suggested that depletion of IB4-positive neurons increases acute nociceptive thresholds to noxious thermal stimuli. The extent to which these non-peptidergic neurons mediate changes in nociception after injury is unknown. Here, we examined the contribution of IB4-positive, non-peptidergic, neurons to thermal and mechanical sensitivity after acute tissue injury. Baseline thermal (radiant heat) and mechanical (von Frey) thresholds were measured in rats prior to injection of IB4-saporin (5 ug/5 ul) into the left sciatic nerve. By two weeks, IB4-saporin-treated animals exhibited pronounced increases in their nociceptive thresholds to thermal and mechanical stimuli. At this time, treatment with NGF (5 ug/50 ul, i.pl.) increased paw thickness in both control and IB4-saporin-treated rats. However, nociceptive thresholds were significantly lowered in control rats, but not in those treated with IB4-saporin. This suggests that IB4-positive neurons contribute to injury-induced changes in thermal and mechanical sensitivity and provide insight into the function of this unique set of primary afferent neurons.
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Role of IB4-binding sensory neurons in the effects of intradermal capsaicin injection.
Vulchanova L, Olson TH, Elde R, Honda CN (2000) Role of IB4-binding sensory neurons in the effects of intradermal capsaicin injection. Neuroscience 2000 Abstracts 212.7. Society for Neuroscience, New Orleans, LA.
Summary: We have shown previously that a unilateral injection of a conjugate of the lectin IB4 and the toxin saporin (IB4-SAP) into sciatic nerve of rats results in loss of IB4-binding neurons and transient increase in thermal and mechanical nociceptive thresholds. The thresholds were maximally increased 10 days post-treatment and returned to baseline levels by day 21. In the present study, we examined the responses of IB4-SAP treated rats after intradermal injection of capsaicin, which results in acute nocifensive behavior followed by thermal and mechanical hyperalgesia. The nocifensive behavior of IB4-SAP treated rats 10, 21 and 42 days post-treatment was 6%, 36% and 47%, respectively, of the behavior of control treated rats. IB4-SAP treated rats injected with capsaicin did not develop thermal or mechanical hyperalgesia at any of the time points examined. These results suggest that the increase in thermal nociceptive thresholds after IB4-SAP treatment is due to loss of VR1-expressing IB4-binding neurons since the nocifensive behavior is most likely mediated by the capsaicin receptor VR1, which also transduces noxious thermal stimuli. In addition, VR1 in surviving neurons may contribute to the recovery of thermal nociceptive thresholds. Finally, our results suggest that IB4-binding neurons are required for development of capsaicin-mediated hyperalgesia, and that the recovery of the responsiveness of IB4-SAP treated rats to noxious stimuli under normal conditions is not accompanied by recovery of the mechanisms underlying hyperalgesia.
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Depletion of IB4-binding sensory neurons results in elevated nociceptive thresholds.
Vulchanova L, Stone LS, Olson T, Riedl MS, Elde R, Honda CN (1999) Depletion of IB4-binding sensory neurons results in elevated nociceptive thresholds. Neuroscience 1999 Abstracts 272.8. Society for Neuroscience, Miami, FL.
Summary: The lectin IB4 binds to and is specifically taken up by a subset of small sensory neurons, proposed to play a role in nociception. To examine the role of these neurons in sensory transmission we used a conjugate of IB4 and the toxin saporin (IB4-sap). IB4-sap (2 µg/5 µl) was injected in the left sciatic nerve of rats. Three days after the injection, the conjugate was visualized in the left L4 and L5 DRG using antisera to either the lectin or saporin. The cells labeled by these antisera were not stained by the Nissl-like marker ethidium bromide, suggesting disruption of their protein synthesis. Twenty one days after the injection there was a 36% reduction in the total number of neurons and a 50% reduction in IB4-binding neurons in L5 DRG of IB4-sap injected rats. Moreover, in dorsal horn of spinal cord, the projection site of the left sciatic nerve was devoid of IB4 binding. P2X3 immunostaining was also dramatically reduced, while the decrease in staining for SP, CGRP and VR1 was less pronounced. The responsiveness of the IB4-sap treated rats to noxious thermal and mechanical stimuli was examined using radiant heat and von Frey filaments, respectively. There was a significant increase in the withdrawal latency to thermal stimuli at day 10 and the withdrawal threshold to mechanical stimuli at day 14 post-treatment. By day 21 both the thermal and mechanical thresholds returned to baseline levels. We have shown that depletion of IB4-binding sensory neurons results in transient elevation of nociceptive thresholds. These findings suggest that IB4-binding neurons mediate the signaling of noxious stimuli and that an efficient compensatory mechanism appears to be activated within days of their loss. Supported by NIH grants DA09641 and DE07288.
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Distinct neurochemical features of acute and persistent pain.
Basbaum AI (1999) Distinct neurochemical features of acute and persistent pain. Proc Natl Acad Sci U S A 96:7739-7743. doi: 10.1073/pnas.96.14.7739
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Tackling pain at the source: New ideas about nociceptors.
Snider WD, McMahon SB (1998) Tackling pain at the source: New ideas about nociceptors. Neuron 20:629-632. doi: 10.1016/s0896-6273(00)81003-x
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