Affiliation:
1. Department of Pharmacology and Therapeutics, University of Wales College of Medicine, Heath Park, Cardiff, UK
Abstract
Abstract
In the rat anococcygeus muscle neostigmine induces atropine-sensitive, significant leftward displacements of the log concentration-response curves to both noradrenaline and 5-hydroxytryptamine. Responses to high K+ were also potentiated by neostigmine. However, high K+ elicited only small and irregular overflows of tritium from [3H]noradrenaline pre-incubated tissues, in contrast to the large overflow elicited by field stimulation. In addition guanethidine blocked responses to field stimulation but not those to high K+. This is consistent with the dose-related tension responses to high K+ being elicited postsynaptically. These results indicate that postsynaptic muscarinic receptors are involved in the potentiation by neostigmine of rat anococcygeus muscle responses to field stimulation or exogenous agonists, possibly by an action on receptor operated ion channels. Additional support for a postsynaptic site of action comes from the failure of neostigmine to potentiate tension responses to nerve or field stimulation in the chick expansor secundariorum, a muscle which is devoid of postsynaptic muscarinic receptors.
Publisher
Oxford University Press (OUP)
Subject
Pharmaceutical Science,Pharmacology
Reference11 articles.
1. M-currents and other potassium currents in bullfrog sympathetic neurones;Adams;J. Physiol.,1982
2. Effects of perfusion with K-rich solution on the noradrenaline content of the rat vas deferens;Bisby;Ibid.,1969
3. The expansor secundariorum of the domestic fowl; a smooth muscle-nerve preparation without cholinergic receptors;Buckley;Br. J. Pharmacol.,1970
4. The isolated expansor secundariorum: a smooth muscle preparation from the wing of the domestic fowl;Buckley;J. Pharm. Pharmacol.,1968
5. Membrane mechanisms associated with muscarinic receptor activation in single cells freshly dispersed from the rat anococcygeus muscle;Byrne;Br. J. Pharmacol.,1987
Cited by
1 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献