Distinct effect of orphanin FQ in nucleus raphe magnus and nucleus reticularis gigantocellularis on the rat tail flick reflex.

Abstract

The aim of the present study is to investigate the effects of orphanin FQ (OFQ) microinjected into the nucleus raphe magnus (NRM) and the nucleus reticularis gigantocellularis (NGC) on pain modulation. The tail-flick latency (TFL) was used as a behavioral index of nociceptive responsiveness. The result showed microinjection of OFQ into the NRM significantly increased the TFL, whereas microinjection of OFQ into the NGC decreased the TFL, suggesting the analgesic effect of OFQ in the NRM and the hyperalgesic effect of OFQ in the NGC. As there are three classes of putative pain modulating neurons in the rostral ventromedial medulla (RVM), the hyperalgesic or analgesic effect of OFQ in the RVM might depend upon the different class of the neurons being acted.

• Authors: Z Yang, Y Zhang, G Wu
• Journal: Neuroscience letters (Neurosci Lett) Vol. 306 Issue 1-2 Pg. 69-72 (Jun 22 2001) ISSN: 0304-3940 [Print] Ireland
• PMID: 11403960 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Opioid Peptides
• Vasodilator Agents
• nociceptin

Topics

• Animals
• Dose-Response Relationship, Drug
• Male
• Medulla Oblongata (cytology, drug effects, metabolism)
• Neural Pathways (cytology, drug effects, metabolism)
• Neurons (cytology, drug effects, metabolism)
• Opioid Peptides (metabolism, pharmacology)
• Pain (drug therapy, metabolism, physiopathology)
• Pain Measurement (drug effects)
• Raphe Nuclei (cytology, drug effects, metabolism)
• Rats
• Rats, Sprague-Dawley
• Reticular Formation (cytology, drug effects, metabolism)
• Vasodilator Agents (metabolism, pharmacology)