targeted-toxins

Rivat C, Vera-Portocarrero LP, Ibrahim MM, Mata HP, Stagg NJ, De Felice M, Porreca F, Malan TP (2009) Spinal NK-1 receptor-expressing neurons and descending pathways support fentanyl-induced pain hypersensitivity in a rat model of postoperative pain. Eur J Neurosci 29:727-737. doi: 10.1111/j.1460-9568.2009.06616.x

Summary: Opioids activate hyperalgesia and allodynia. The authors test the hypothesis that NK-1 receptor-containing ascending pathways play a role in sensitivity to fentanyl. Rats received an intrathecal injection of SP-SAP (Cat. #IT-07), and controls received saporin (Cat. #PR-01). The data indicate that these ascending pathways have a role in fentanyl-induced hyperalgesia.

Related Products: SP-SAP (Cat. #IT-07), Saporin (Cat. #PR-01)

Frechette M, Rennie K, Pappas BA (2009) Developmental forebrain cholinergic lesion and environmental enrichment: behaviour, CA1 cytoarchitecture and neurogenesis. Brain Res 1252:172-182. doi: 10.1016/j.brainres.2008.11.082

Summary: The authors investigated the effect of neonatal cholinergic lesions on plasticity in the presence or absence of enrichment. Each lateral ventricle of 7 day-old rats received 300 ng of 192-IgG-SAP (Cat. #IT-01). Although the lesions did not attenuate neurobehavioral plasticity, there were several physiological changes that occurred despite the environmental enrichment.

Related Products: 192-IgG-SAP (Cat. #IT-01)

Little CM, Coons KD, Sengelaub DR (2009) Neuroprotective effects of testosterone on the morphology and function of somatic motoneurons following the death of neighboring motoneurons. J Comp Neurol 512:359-372. doi: 10.1002/cne.21885

Summary: Atrophy of androgen-sensitive motoneurons due to proximity to damaged motoneurons can be attenuated by testosterone. This work examined whether typical motoneurons respond in the same way. Rats received 5-ng injections of CTB-SAP (Cat. #IT-14) that eliminated motoneurons innervating the vastus medialis muscle. Partial motoneuron depletion resulted in atrophy of the remaining quadriceps motoneurons; this was attenuated by the administration of testosterone.

Related Products: CTB-SAP (Cat. #IT-14)

Dashniani MG, Beseliia GV, Maglakelidze GA, Burdzhanadze MA, Chkhikvishvili N (2009) Effects of the selective lesions of cholinergic septohippocampal neurons on different forms of memory and learning process. Georgian Med News 166:81-85.

Summary: The hippocampus is crucial for the ability to recollect everyday events and factual knowledge. Here the authors looked at the role of the septo-hippocampal cholinergic system of the medial septum in learning and memory. Rats received 200 ng injections of 192-IgG-SAP (Cat. #IT-01) into the medial septum. Mouse IgG-SAP (Cat. #IT-18) was used as a control. The data suggest that although the septo-hippocampal region is essential for spatial learning, hippocampal acetyl cholinesterase may not be essential for all types of hippocampal-dependent memory.

Related Products: 192-IgG-SAP (Cat. #IT-01), Mouse IgG-SAP (Cat. #IT-18)

Loyd DR, Wang X, Murphy AZ (2008) Sex differences in micro-opioid receptor expression in the rat midbrain periaqueductal gray are essential for eliciting sex differences in morphine analgesia. J Neurosci 28:14007-14017. doi: 10.1523/JNEUROSCI.4123-08.2008

Summary: The authors test whether the periaqueductal gray (PAG), that contains a dense population of µ-opioid receptor (MOR)-expressing neurons, is sexually dimorphic. Rats were injected with 3 pmol of Dermorphin-SAP (Cat. #IT-12) into the PAG. Blank-SAP (Cat. #IT-21) was used as a control. Both behavioral and immunohistochemical evidence suggest that differential expression of MOR-expressing neurons in the PAG between male and female rats accounts for the difference in response to morphine.

Related Products: Dermorphin-SAP / MOR-SAP (Cat. #IT-12), Blank-SAP (Cat. #IT-21)

Burk JA, Lowder MW, Altemose KE (2008) Attentional demands for demonstrating deficits following intrabasalis infusions of 192 IgG-saporin. Behav Brain Res 195:231-238. doi: 10.1016/j.bbr.2008.09.006

Summary: Attentional processing has been shown to be dependent on basal forebrain cholinergic inputs to the cerebral cortex. In this work the authors wished to specify which components should be used to demonstrate deficits following the loss of these neurons. Rats received 200 ng intrabasalis infusions of 192-IgG-SAP (Cat. #IT-01). Testing of lesioned animals indicated that attentional deficits are due to increase of overall attentional task demands as opposed to any single task parameter.

Related Products: 192-IgG-SAP (Cat. #IT-01)

Fitz NF, Gibbs RB, Johnson DA (2008) Selective lesion of septal cholinergic neurons in rats impairs acquisition of a delayed matching to position T-maze task by delaying the shift from a response to a place strategy. Brain Res Bull 77:356-360. doi: 10.1016/j.brainresbull.2008.08.016

Summary: It has been theorized that the effect of cholinergic lesions of the medial septum on learning depend on the stressful nature of the task being learned. The authors injected 0.2 µg of 192-IgG-SAP (Cat. #IT-01) into the medial septum of rats then examined the strategies used by these animals to learn a delayed matching to position T-maze task. Lesioned animals were less able to switch from one strategy to another, indicating that this mechanism is the primary one affected by septal cholinergic lesions.

Related Products: 192-IgG-SAP (Cat. #IT-01)

Milstein JA, Dalley JW, Robbins TW (2010) Methylphenidate-induced impulsivity: pharmacological antagonism by beta-adrenoreceptor blockade. J Psychopharmacol 24:309-321. doi: 10.1177/0269881108098146

Summary: In this work bilateral 20 ng intracortical injections of anti-DBH-SAP (Cat. #IT-03) were used to examine the role of noradrenergic neurons in the control of psychostimulant-induced impulsivity. Although β-adrenoreceptor blockade abolished this impulsivity, lesioning noradrenergic neurons in the cortex had no effect. The data indicate that modulation of impulsive responding in this model is controlled by β-adrenoreceptors.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Zhang W, Gardell S, Zhang D, Xie JY, Agnes RS, Badghisi H, Hruby VJ, Rance N, Ossipov MH, Vanderah TW, Porreca F, Lai J (2009) Neuropathic pain is maintained by brainstem neurons co-expressing opioid and cholecystokinin receptors. Brain 132:778-787. doi: 10.1093/brain/awn330

Summary: It has been hypothesized that a subset of rostral ventromedial medulla (RVM) neurons co-expressing the cholecystokinin type 2 receptor and the mu-opioid receptor are responsible for the maintenance of neuropathic pain. Rats were treated with 50-ng bilateral RVM injections of Dermorphin-SAP (Cat. #IT-12), CCK-SAP (Cat. #IT-31), or saporin (Cat. #PR-01) as a control. Lesion of the RVM neurons prevented hyperalgesia in response to CCK treatment, and shortened abnormal pain states caused by sciatic nerve injury.

Related Products: Dermorphin-SAP / MOR-SAP (Cat. #IT-12), CCK-SAP (Cat. #IT-31), Saporin (Cat. #PR-01)

Wiley RG, Moore SA, Kline IV RH (2008) Analysis of inhibitory phase of formalin test: Effects of specific neural lesions. Neuroscience 2008 Abstracts 772.4/MM19. Society for Neuroscience, Washington, DC.

Summary: The formalin test has been widely used as a model of persistent pain. The 90 mins of formalin-induced nocifensive responding can be divided into two phases (phase 1, first ~10 mins; phase 2, last ~60 mins) separated by a period of reduced responding (interphase, IP), that has received relatively little attention. Behavioral inhibition during the IP of the formalin test has been associated with electrophysiological evidence of inhibition of dorsal horn nociceptive neurons (Henry et al, Pain, 82:57, 1999), probably due, at least in part, to local spinal mechanisms. Behavioral inhibition during IP has been shown to be enhanced by morphine and suppressed by naloxone. In the present study, we sought to determine the effect of selective depletion of specific dorsal horn interneurons known to be involved in nociception, i.e. neurons expressing NPY1R, GalR1 or MOR, or selective destruction of cerebral noradrenergic neurons or spinal cord projecting 5-HT neurons on formalin-induced nociceptive behavior, with particular attention to IP. Type-selective lesions were produced by lumbar intrathecal injection of NPY-saporin, galanin-saporin or dermorphin-saporin, respectively. Cerebral noradrenergic neurons and spinally projecting 5-HT neurons were destroyed using the immunotoxins, anti-DBH-saporin (intracerebroventricular) or anti-SERT-saporin (lumbar intrathecal), respectively. Partial loss of dorsal horn interneurons expressing NPY1R or GalR1 decreased nocifensive responding during IP and phase 2 of the formalin test, while partial loss of MOR-expressing dorsal horn interneurons increased nocifensive responding during IP and during phase 2. Both antiDBH-sap and antiSERT-sap decreased responding during IP, without effects on either phase 1 or 2. These results suggest that the apparent anti-nociception during IP and phase 2 produced by loss of NPY1R- and GalR1-expressing dorsal horn neurons is due to increased inhibition over excitation/facilitation of nociceptive projection neurons, whereas depletion of MOR-expressing interneurons produces the opposite effect. The apparent enhanced nociception during IP, but not phase I and II, produced by anti-DBH-sap and anti-SERT-sap suggests that these neural systems serve to enhance the excitability of nociceptive projection neurons during the formalin IP. Electrophysiologic and pharmacologic studies of formalin IP in selectively lesioned animals combined with the above behavioral findings may reveal new insights into endogenous modulation of nocifensive motor responses and/or nociception.

Related Products: NPY-SAP (Cat. #IT-28), Anti-SERT-SAP (Cat. #IT-23), Galanin-SAP (Cat. #IT-34), Anti-DBH-SAP (Cat. #IT-03), Dermorphin-SAP / MOR-SAP (Cat. #IT-12)