Nociceptin inhibits electric field stimulation-induced cholinergic constrictions in rat airways

• Published in: Acta pharmacologica Sinica Vol. 21; no. 10; pp. 945 - 948
• Main Authors: Wu, Y, Fang, L B, Yang, Q H
• Format: Journal Article
• Language: English
• Published: United States 01.10.2000
• Subjects: 3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cyclohexyl)-benzeneacetamide, (trans)-Isomer - pharmacology; Animals; Bronchoconstriction - drug effects; Cholinergic Fibers - physiology; Electric Stimulation; In Vitro Techniques; Male; Nociceptin; Opioid Peptides - pharmacology; Rats; Rats, Sprague-Dawley; Receptors, Opioid - agonists; Receptors, Opioid, kappa - agonists; Trachea - physiology
• ISSN: 1671-4083

To study the effect of nociceptin (orphanin FQ), a newly discovered heptadecapeptide, on cholinergic constrictions in isolated trachea and bronchus of rat. The electric field stimulation (EFS) induced a monophasic constriction, which was due to an activation of the cholinergic nerves. Nociceptin 0.001-0.1 mumol/L inhibited cholinergic constriction in a concentration-dependent manner. IC50 (95% of confidence limits) were 0.06 (0.04-0.08) mumol/L and 0.07 (0.05-0.1) mumol/L in tracheae and bronchi respectively. The constrictions inhibited by nociceptin 0.01 mumol/L in traheae and bronchi were (58 +/- 32)% and (60 +/- 26)% respectively compared with the control, in which nociceptin was not applied. After pretreatment with naloxone 0.1 mumol/L, the constrictions were (60 +/- 19)% and (54 +/- 20)% (P > 0.05 vs the above figures). However, the constrictions induced by exogenous acetylcholine were unaffected by nociceptin 0.01 mumol/L. kappa-Opioid receptor agonist, U-50488H (0.01-1 mumol/L) did not affect the EFS-induced cholinergic constrictions in rat airways. Nociceptin inhibits EFS-induced cholinergic constriction, which is not affected by naloxone in rat airways.