Please use this identifier to cite or link to this item:
Title: Involvement of neuropeptide Y in the acute, chronic and withdrawal responses of morphine in nociception in neuropathic rats: Behavioral and neuroanatomical correlates
Authors: Upadhya, Manoj A.
Dandekar, Manoj P.
Kokare, Dadasaheb M.
Singru, Praful S.
Dept. of Biology
Keywords: Morphine
Neuropeptide Y
Neuropathic pain
Thermal paw
Issue Date: Aug-2009
Publisher: Elsevier B.V.
Citation: Neuropeptides, 43(4).
Abstract: Although morphine is a potent antinociceptive agent, its chronic use developed tolerance in neuropathic pain (NP). Furthermore, opioid antagonist naloxone attenuated the antinociceptive effect of neuropeptide Y (NPY). The present study investigated the role of NPY and NPY Y1/Y5 receptors in acute and chronic actions of morphine in neuropathic rats using thermal paw withdrawal test and immunocytochemistry. In acute study, intracerebroventricular (icv) administration of morphine, NPY or NPY Y1/Y5 receptors agonist [Leu31, Pro34]-NPY produced antinociception, whereas selective NPY Y1 receptors antagonist BIBP3226 caused hyperalgesia. While NPY or [Leu31, Pro34]-NPY potentiated, BIBP3226 attenuated morphine induced antinociception. Chronic icv infusion of morphine via osmotic minipumps developed tolerance to its antinociceptive effect, and produced hyperalgesia following withdrawal. However, co-administration of NPY or [Leu31, Pro34]-NPY prevented the development of tolerance and withdrawal hyperalgesia. Sciatic nerve ligation resulted in significant increase in the NPY-immunoreactive (NPY-ir) fibers in ventrolateral periaqueductal gray (VLPAG) and locus coeruleus (LC); fibers in the dorsal part of dorsal raphe nucleus (DRD) did not respond. While chronic morphine treatment significantly reduced NPY-ir fibers in VLPAG and DRD, morphine withdrawal triggered significant augmentation in NPY-immunoreactivity in the VLPAG. NPY-immunoreactivity profile of LC remained unchanged in all the morphine treatment conditions. Furthermore, removal of sciatic nerve ligation reversed the effects of NP, increased pain threshold and restored NPY-ir fiber population in VLPAG. NPY, perhaps acting via Y1/Y5 receptors, might profoundly influence the processing of NP information and interact with the endogenous opioid system primarily within the framework of the VLPAG.
ISSN: 0143-4179
Appears in Collections:JOURNAL ARTICLES

Files in This Item:
There are no files associated with this item.

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.