Targeting Topics 16q3

Non-genotoxic conditioning for hematopoietic stem cell transplantation using a hematopoietic-cell-specific internalizing immunotoxin.

Palchaudhuri R, Saez B, Hoggatt J, Schajnovitz A, Sykes DB, Tate TA, Czechowicz A, Kfoury Y, Ruchika F, Rossi DJ, Verdine GL, Mansour MK, Scadden DT.

Nat Biotechnol 34(7):738-745, 2016. PMID: 27272386

see cover article

Retinal Waves Modulate an Intraretinal Circuit of Intrinsically Photosensitive Retinal Ganglion Cells.

Arroyo DA, Kirkby LA, Feller MB.

J Neurosci 36(26):6892-6905, 2016. PMID: 27358448

The researchers explore the neural circuits underlying the ipRGC driven light responses of the developing retina and the mechanisms by which retinal waves regulate these circuits. They demonstrate that, even in the presence of cholinergic waves, ipRGC gap junction microcircuits propagate light-driven signals, thus strongly contributing to the overall light response of the developing retina. Following fixation, retinas were washed in PBS and remounted onto a new piece of filter paper. They were incubated in blocking buffer and then in primary immunoreaction solution, 1:2500 rabbit anti-melanopsin (Cat. #AB-N38). Results show that, during development, ipRGCs form extensive gap junction microcircuits that shape the early retinal light response. Retinal waves exert a far-reaching, neuromodulatory influence on these circuits via dopaminergic modulation of gap junctions, thus potentially impacting the processing of early visual input.

Gi-Protein Coupled 5-HT1B/D Receptor Agonist Sumatriptan Induces Type I Hyperalgesic Priming.

Araldi D, Ferrari LF, Levine JD.

Pain 2016. PMID: 27075428

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.

Dynamics of spinal microglia repopulation following an acute depletion.

Yao Y, Echeverry S, Shi XQ, Yang M, Yang QZ, Wang GY, Chambon J, Wu YC, Fu KY, De Koninck Y, Zhang J.

Sci Rep 6:22839, 2016. PMID: 26961247

This study confirms that similar to microglia in the brain, spinal microglia can repopulate rapidly following elimination, which is driven essentially by a self-renewal process. To deplete microglia in spinal cords, Mac-1-SAP (Cat. #IT-06) was injected i.t. (7 μl, 1.6  μg/μl) at the level of L4-L5 in mouse. The results support the concept that microglia repopulation, whether in the brain or in the spinal cord, is the consequence of onsite resident microglia proliferation. Newly generated microglia are fully functional and are able to respond to peripheral nerve injury and contribute to the development of neuropathic pain.

Brainstem opioidergic system is involved in early response to experimental SAH.

Cetas JS, McFarlane R, Kronfeld K, Smitasin P, Liu JJ, Raskin JS.

Transl Stroke Res 6(2):140-147, 2015. PMID: 25417789

Subarachnoid hemorrhage (SAH) is a particular type of stroke that has high morbidity and mortality. The damage due to SAH is manifested in numerous ways, including global hypoperfusion, neuronal death, infarcts, microhemorrhages, and cortical spreading depression – as well as other acute autonomic dysfunctions. In this work the authors investigated how some autonomic and sensorimotor systems in the rostral ventromedial medulla (RVM) are involved in the maintenance of cerebral blood flow in a SAH model. Rats received 1 pmol total of dermorphin-SAP (Cat. #IT-12) in bilateral injections to the RVM. Blank-SAP (Cat. #IT-21) was used as a control. The results indicate that μ-opioid receptor-expressing cells in the RVM are important in reducing mortality rates after SAH.

Ablation of KNDy neurons results in hypogonadotropic hypogonadism and amplifies the steroid-induced LH surge in female rats.

Mittelman-Smith MA, Krajewski-Hall SJ, McMullen NT, Rance NE.

Endocrinology 157(5):2015-2027, 2016. PMID: 26937713

KNDy neurons are a subpopulation of neurons in the infundibular nucleus that coexpress estrogen receptor α, kisspeptin, and neurokinin B (NKB) mRNA. Previous work indicated that altered signaling from KNDy neurons may play a role in the low levels of circulating sex steroids found in hypogonadotropic hypogonadism. Rats received bilateral 10-ng injections of NK3-SAP (Cat. #IT-63) dorsal to the arcuate nucleus. Blank-SAP (Cat. #IT-21) was used as control. In animals with intact ovaries the NK3-SAP lesion resulted in hypogonadotropic hypogonadism. In contrast, the LH surge in lesioned ovariectomized rats was 3-fold higher, demonstrating that KNDy neurons are integral for the control of serum LH levels, estrous cyclicity, and may also have some control over the magnitude of the LH surge.

Involvement of nigral oxytocin in locomotor activity: A behavioral, immunohistochemical and lesion study in male rats.

Angioni L, Cocco C, Ferri GL, Argiolas A, Melis MR, Sanna F.

Horm Behav 83:23-38, 2016. PMID: 27189764

Oxytocin is well known for its hormonal role in lactation and parturition, but also exerts widespread actions in central nervous system. Previous experiments revealed the existence of a correlation between the changes in locomotor activity found in Oxytocin-SAP-treated rats and the extent of the changes in nigral TH and vesicular glutamate transporters immunoreactivity, provide support for a modulatory role of oxytocin on locomotor activity at the level of the substantia nigra. The day after a prior assessment of spontaneous locomotor activity, rats were randomly injected bilaterally with 0.3 μL of Oxytocin-SAP (Cat. #IT-46, 60 ng/μL/site), or with the same amount of Blank-SAP (Cat. #IT-21, 60 ng/μL/site) or with vehicle (0.3 μL/site of PBS, pH 7.4). Whether oxytocin may be considered as a target for controlling motor disturbances, as those occurring in Parkinson’s disease and/or in other motor disturbances related to basal ganglia dysfunctions, remains to be evaluated

Possible Involvement of the Rat Hypothalamo-Neurohypophysial/-Spinal Oxytocinergic Pathways in Acute Nociceptive Responses.

Matsuura T, Kawasaki M, Hashimoto H, Yoshimura M, Motojima Y, Saito R, Ueno H, Maruyama T, Ishikura T, Sabanai K, Mori T, Ohnishi H, Onaka T, Sakai A, Ueta Y.

J Neuroendocrinol 28(6)2016. PMID: 27144381

It has been suggested that the amplification of GABAergic neurons in the inhibitory system induces the selective inhibition by Oxytocin (OXT) of excitability in the spinal cord, and the pain transmitted from the periphery to the dorsal horn of the spinal cord by this action may be attenuated at the spinal cord level. Rats were injected IT with Oxytocin-SAP (Cat. #IT-46) dissolved in saline (0.06 μg/μl), Blank-SAP (Cat. #IT-21) dissolved in saline (0.06 μg/μl), or saline. Formalin-induced acute nociception activated OXT-containing cells in both the magnocellular and parvocellular divisions of hypothalamus, and that the parvocellular division remains activated longer than the magnocellular division. Acute nociception-induced activation of the hypothalamo-neurohypophysial system caused elevation of plasma OXT levels. In addition, the OXTergic spinal pathway may be involved in pain modulation via OXTRs in the spinal cord.

Locus coeruleus noradrenergic innervation of the amygdala facilitates alerting-induced constriction of the rat tail artery.

Mohammed M, Kulasekara K, Ootsuka Y, Blessing WW.

Am J Physiol Regul Integr Comp Physiol 310(11):R1109-19, 2016. PMID: 27101292

The researchers tested the hypothesis that release of noradrenaline within the amygdala is important for the occurrence of SCVARS (sympathetic cutaneous vasoconstrictor alerting responses). A long-shanked 5-μl glass micropipette calibrated in 100-nl steps, was filled with vehicle or Anti-DBH-SAP (Cat. #IT-03). Anti-DBH-SAP (5 μg in 250 nl) or vehicle was injected into the amygdala during ∼1 min, and the pipette was left in place for an additional The locus coeruleus has been implicated in many aspects of emotional arousal, so that functional inhibition of the extensive locus coeruleus-derived noradrenergic innervation of centers known to be important in emotional arousal, including the amygdala, is likely to contribute to the therapeutic actions of clonidine-like agents. The locus coeruleus also has major reciprocal connections with the orexin-synthesizing neurons in the hypothalamus, and rats with genetically lesioned orexin receptor neurons (alternatively, oen could lesion with Orexin-SAP, Cat. #IT-20) have reduced emotional arousal as reflected in reduced SCVAR responses to alerting stimuli.

Functional characterization of a mouse model for central post-stroke pain.

Gritsch S, Bali KK, Kuner R, Vardeh D.

Molecular Pain 12:1744806916629049, 2016. PMID:27030713

While clinical evidence has pointed toward central pain pathway dysfunction in central post-stroke pain (CPSP), the underlying mechanisms have not been defined. In this work the authors created a mouse model of CPSP through lesions of the thalamic ventral posterolateral nucleus. In order to examine the role of neurokinin-1 receptor-expressing (NK1R) neurons in lamina I/III of the spinal cord in the development and maintenance of CPSP the authors administered 1 μmol intrathecal injections of SSP-SAP (Cat. #IT-11). Saporin (Cat. #PR-01) was used as a control. While the NK1R+ neurons in the spinal cord were not involved in establishing CPSP, the data indicate that sensory changes in the mice are comparable to those observed in human patients with CPSP.

Role of the RVM in Descending Pain Regulation Originating from the Cerebrospinal Fluid-Contacting Nucleus.

Fei Y, Wang X, Chen S, Zhou Q, Zhang C, Li Y, Sun L, Zhang L.

Neurochem Res 41(7):1651-1661, 2016. PMID: 26961890

The researchers investigated whether the CSF-contacting nucleus contributed to descending pain modulation in normal and neuropathic rats, and detected the 5-HT expression changes in both RVM and spinal dorsal cord. They also detected the possible anatomical and function correlation between the CSF-contacting nucleus and the RVM. Targeted ablation of the CSF-contacting nucleus was performed using CTB-SAP (Cat. #IT-14; 500 ng/3 μl), which was administered i.c.v. to the normal rats and rats 7 days before the CCI procedure. Based on the findings of the present study, they believe that the CSF-contacting nucleus may act as a component of descending pain regulation system. RVM, which acts as an important brain nucleus, is involved in the relay of nociceptive information between the CSF-contacting nucleus and spinal cord. Moreover, RVM 5-HT system plays a critical role in descending pain inhibition originating from the CSF-contacting nucleus.

Effects of central administration of oxytocin-saporin cytotoxin on chronic inflammation and feeding/drinking behaviors in adjuvant arthritic rats.

Matsuura T, Kawasaki M, Hashimoto H, Yoshimura M, Motojima Y, Saito R, Ueno H, Maruyama T, Sabanai K, Mori T, Ohnishi H, Sakai A, Ueta Y.

Neurosci Lett 621:104-110, 2016. PMID: 27060190

In the present study, Oxytocin-SAP, which chemically disrupts oxytocin (OXT signaling was administered centrally and an OXT receptor (OXTR) antagonist administered peripherally to determine whether central and peripheral OXT is involved in chronic inflammation and feeding/drinking behavior in adjuvant arthritis (AA) rats. Rats were injected i.t. with Oxytocin-SAP (Cat. #IT-46) or Blank-SAP (Cat. #IT-21) dissolved in saline (0.06 μg/μl). The results demonstrated that the arthritis index values were significantly enhanced and suppression of food intake was transiently attenuated in Oxytocin-SAP treated rats when AA developed, The arthritis index and food intake did not significantly change in the OXTR antagonist i.p.-injected rats. These results suggest that central oxytocinergic pathways may be involved in anti-inflammation at the spinal level and suppression of feeding behavior at the forebrain-brainstem level in AA rats.