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Effects of morphine, H‐Tyr‐ d ‐Arg‐Phe‐Lys‐NH 2 (DALDA) and B‐HT920 on non‐cholinergic nerve‐mediated bronchoconstriction in pithed guinea‐pigs
Author(s) -
Rechtman M.P.,
Boura A.L.A.,
King R.G.,
Olley J.E.,
Schiller P.W.
Publication year - 1990
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1990.tb12699.x
Subject(s) - bronchoconstriction , morphine , cholinergic , guinea pig , chemistry , pharmacology , lysergic acid diethylamide , stereochemistry , endocrinology , medicine , serotonin , receptor , biochemistry , asthma
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 μ‐receptor agonist, H‐Tyr‐ d ‐Arg‐Phe‐Lys‐NH 2 (DALDA, 0.1–1 mg kg −1 , i.v.) or the α 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 μ‐opioid receptors or α 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.