Nociceptin inhibits electric field stimulation-induced cholinergic constrictions in rat airways.
OBJECTIVE
To study the effect of nociceptin (orphanin FQ), a newly discovered heptadecapeptide, on cholinergic constrictions in isolated trachea and bronchus of rat.


METHODS
The electric field stimulation (EFS) induced a monophasic constriction, which was due to an activation of the cholinergic nerves.


RESULTS
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.


CONCLUSIONS
Nociceptin inhibits EFS-induced cholinergic constriction, which is not affected by naloxone in rat airways.
Wu
Y
Y
Department of Pharmacology, School of Medicine, Zhejiang University, Hangzhou 310006, China. sbms@mail.hz.zj.cn
Fang
L B
LB
Yang
Q H
QH
D019900:3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cyclohexyl)-benzeneacetamide, (trans)-Isomer / Q000494:pharmacology; D000818:Animals; D016084:Bronchoconstriction / Q000187:drug effects*; D002799:Cholinergic Fibers / Q000502:physiology*; D004558:Electric Stimulation; D066298:In Vitro Techniques; D008297:Male; D018847:Opioid Peptides / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011957:Receptors, Opioid / Q000819:agonists*; D017473:Receptors, Opioid, kappa / Q000819:agonists; D014132:Trachea / Q000502:physiology*; D000097629:Nociceptin
D019900:3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cyclohexyl)-benzeneacetamide, (trans)-Isomer; D018847:Opioid Peptides; D011957:Receptors, Opioid; D017473:Receptors, Opioid, kappa; D000097629:Nociceptin