Effects of morphine, H-Tyr-D-Arg-Phe-Lys-NH2 (DALDA) and B-HT920 on non-cholinergic nerve-mediated bronchoconstriction in pithed guinea-pigs.
1. Electrical stimulation (1 ms, 5 Hz, 80 V) for 5 or 15 s at the level of C4-T1 in the spinal canal of artificially respired pithed guinea-pigs (which had received intravenously (i.v.) (+)-tubocurarine chloride 2 mg kg-1, atropine sulphate 2 mg kg-1 and pentolinium tartrate 5 mg kg-1) caused constriction of airways, indicated by increased insufflation pressure. 2. This non-cholinergic constriction was inhibited by morphine (1-3 mg kg-1, i.v.), the peripherally acting mu-receptor agonist, H-Tyr-D-Arg-Phe-Lys-NH2 (DALDA, 0.1-1 mg kg-1, i.v.) or the alpha 2-adrenoceptor agonist B-HT920 (1-3 mg kg-1, i.v.). 3. The effects of either morphine (3 mg kg-1, i.v.) or DALDA (1 mg kg-1, i.v.) were inhibited by naloxone (3 mg kg-1, i.v.). Idazoxan (3 mg kg-1, i.v.) inhibited the anti-constrictor effect of B-HT920 (3 mg kg-1, i.v.), but not that of DALDA (0.1 mg kg-1, i.v.). 4. Thus activation of peripheral mu-opioid receptors or alpha 2-adrenoceptors inhibits airways constriction induced by non-cholinergic nerve stimulation in the pithed guinea-pig. This preparation therefore provides a further method for the in vivo examination of the effects of drugs on non-cholinergic tracheobronchial constrictor nerve function.
Rechtman
M P
MP
Department of Pharmacology, Monash University, Clayton, Victoria, Australia.
Boura
A L
AL
King
R G
RG
Olley
J E
JE
Schiller
P W
PW
D000316:Adrenergic alpha-Agonists / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D000595:Amino Acid Sequence; D000818:Animals; D001381:Azepines / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D016084:Bronchoconstriction / Q000187:drug effects* / Q000502:physiology; D003655:Decerebrate State; D004558:Electric Stimulation; D006168:Guinea Pigs; D008297:Male; D008969:Molecular Sequence Data; D009020:Morphine / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D009842:Oligopeptides / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D010525:Peripheral Nerves / Q000187:drug effects; D011957:Receptors, Opioid / Q000187:drug effects*; D017450:Receptors, Opioid, mu
D000316:Adrenergic alpha-Agonists; D001381:Azepines; D009842:Oligopeptides; D011957:Receptors, Opioid; D017450:Receptors, Opioid, mu; C063076:tyrosyl-arginyl-phenylalanyl-lysinamide; D009020:Morphine; C024763:talipexole