title: Nocistatin reverses the effect of orphanin FQ/nociceptin in antagonizing morphine analgesia.
abstract: Nocistatin is a recently characterized neuropeptide derived from the preprohormone containing nociceptin (Orphanin FQ, OFQ). Nocistatin was reported to antagonize OFQ induced allodynia, hyperalgesia and prostaglandin E2-elicited pain responses. The aim of the present study was to determine whether nocistatin, injected intracerebroventricularly (i.c.v.), would reverse the anti-morphine effect of OFQ in rats using the tail-flick latency (TFL) as the nociceptive index. I.c.v. injection of nocistatin at doses of 0.005, 0.05, 0.5, 5, 50, and 500 ng produced no significant changes in the basal TFL, nor did it affect morphine analgesia. However, it significantly reversed the antagonistic effect of OFQ on morphine analgesia when co-injected i.c.v. at doses of 0.05, 0.5, 5, 50 and 500 ng per rat with OFQ. The dose-response curve was bell-shaped and the most effective dose was 0.5 ng. The results suggest that nocistatin can reverse the anti-morphine effect of OFQ in rat brain.
authors: Neuroscience Research Institute, Beijing Medical University, China.
authors: C S
authors: CS
authors: Zhao
authors: B S
authors: BS
authors: Li
authors: G Y
authors: GY
authors: Zhao
authors: H X
authors: HX
authors: Liu
authors: F
authors: F
authors: Luo
authors: Y
authors: Y
authors: Wang
authors: J H
authors: JH
authors: Tian
authors: J K
authors: JK
authors: Chang
authors: J S
authors: JS
authors: Han
mesh_terms: D000698:Analgesia; D000701:Analgesics, Opioid / Q000037:antagonists & inhibitors*; D000818:Animals; D005260:Female; D007276:Injections, Intraventricular; D009020:Morphine / Q000037:antagonists & inhibitors*; D018847:Opioid Peptides / Q000037:antagonists & inhibitors* / Q000494:pharmacology*; D010147:Pain Measurement / Q000379:methods; D051381:Rats; D017207:Rats, Sprague-Dawley; D011930:Reaction Time / Q000502:physiology; D013623:Tail / Q000502:physiology; D000097629:Nociceptin
chemical_list: D000701:Analgesics, Opioid; D009020:Morphine; D018847:Opioid Peptides; D000097629:Nociceptin; C111148:nocistatin