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COMPARISON OF THE EFFECTS OF BRETYLIUM, GUANETHIDINE AND BETHANIDINE ON SMOOTH MUSCLE RESPONSES TO DIFFERENT RATES OF SYMPATHETIC NERVE STIMULATION
Author(s) -
GREEN A. F.,
ROBSON R. D.
Publication year - 1964
Publication title -
british journal of pharmacology and chemotherapy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0366-0826
DOI - 10.1111/j.1476-5381.1964.tb02039.x
Subject(s) - guanethidine , bretylium , stimulation , medicine , endocrinology , chemistry , vasoconstriction , contraction (grammar) , anesthesia , adrenergic , receptor
The relative effects of bretylium, guanethidine and bethanidine on smooth muscle responses to different rates of sympathetic nerve stimulation have been compared. The responses studied were vasoconstriction in the femoral vascular bed and contraction of the spleen in anaesthetized cats, vasoconstriction in perfused ears of rabbits and inhibition of pendular movements in rabbit isolated ileum preparations. Except in the isolated ileum, the action of bretylium on curves relating the frequency of nerve stimulation and the effect on response was different from that of guanethidine. Whereas bretylium caused relatively greater inhibition of responses to high stimulus frequencies and depressed the slopes of the curves, guanethidine preferentially suppressed responses to low stimulus frequencies and caused roughly parallel shifts of the curves. In each situation tested bethanidine was the most potent of the three blocking agents and in general its effect on frequency/response curves was intermediate between those of bretylium and guanethidine.