Neuronal muscarinic receptors attenuate vagally‐induced contraction of feline bronchial smooth muscle

L. C. Blaber, Allison D. Fryer, Jennifer Maclagan

Research output: Contribution to journalArticlepeer-review

103 Scopus citations


In anaesthetized cats, stimulation of the vagus nerves produced bradycardia and a bronchoconstriction which was measured as an increase in lung resistance (RL) and a fall in dynamic lung compliance (Cdyn); these effects were abolished by atropine. Gallamine potentiated vagally‐mediated changes in RL and Cdyn at doses that blocked muscarinic receptors in the heart and inhibited neuromuscular transmission. (+)‐Tubocurarine and suxamethonium did not affect the response of the lung or the heart to vagal stimulation. Bronchoconstriction induced by intravenous acetylcholine was not potentiated by gallamine, indicating that postsynaptic muscarinic receptors in the lung and changes in muscle tone were not involved. Potentiation of vagally‐induced bronchoconstriction appears to be due to blockade of inhibitory muscarinic receptors located in the pulmonary parasympathetic nerves innervating both central and peripheral airways. Pilocarpine was an agonist for these neuronal receptors as it inhibited vagally‐induced bronchoconstriction at low doses (10 ng to 1 μg kg−1). The results demonstrate that gallamine is an antagonist and pilocarpine an agonist at neuronal muscarinic receptors which attenuate parasympathetic nerve activity in feline lung. 1985 British Pharmacological Society

Original languageEnglish (US)
Pages (from-to)723-728
Number of pages6
JournalBritish Journal of Pharmacology
Issue number3
StatePublished - Nov 1985
Externally publishedYes

ASJC Scopus subject areas

  • Pharmacology


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