Microinjection of neuropeptide Y into periaqueductal grey produces anti-nociception in rats with mononeuropathy.
The present study was carried out to investigate the effects of neuropeptide Y (NPY) in the midbrain periaqueductal grey (PAG) on the nociceptive modulation in mononeuropathic rats. NPY was microinjected into the PAG. The latency of paw withdrawal (PWL), assessed by the hot-plate (52  ) and the Randall Selitto test, was measured. Intra-PAG administration of 0.05, 0.1 and 0.2 nmol of NPY significantly increased the PWLs in a dose-dependent manner. Co-administration of 0.2 nmol of NPY(28-36) and 5.5 nmol of naloxone significantly attenuated the NPY-induced increase in PWLs. The results suggest that Y(1) receptor may mediate NPY-induced anti-nociception, and that the opioid receptors in PAG may also be involved in this process in mononeuropathic rats.
Department of Physiology, Linyi medical college, Linyi 276002, Shangdong Province, China. jiazhenw@163.net
Jia-Zhen
JZ
Wang
D000700:Analgesics / Q000494:pharmacology*; D000818:Animals; D008297:Male; D008845:Microinjections; D020422:Mononeuropathies / Q000503:physiopathology; D009478:Neuropeptide Y / Q000494:pharmacology*; D009619:Nociceptors / Q000187:drug effects*; D010146:Pain / Q000503:physiopathology*; D017288:Pain Threshold / Q000187:drug effects; D010487:Periaqueductal Gray / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley
D000700:Analgesics; D009478:Neuropeptide Y