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Effects of amosulalol on the electrical responses of guinea‐pig vascular smooth muscle to adrenoceptor activation
Author(s) -
Fujioka Masahiko,
Suzuki Hikaru
Publication year - 1985
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.1476-5381.1985.tb12933.x
Subject(s) - phentolamine , yohimbine , isoprenaline , prazosin , vascular smooth muscle , medicine , endocrinology , stimulation , mesenteric vein , phenoxybenzamine , anatomy , artery , propranolol , chemistry , smooth muscle , receptor , portal vein , antagonist
1 The effects of amosulalol, a newly synthesized sulphonamide‐substituted phenylethylamine derivative, on electrical responses of smooth muscle cells of the guinea‐pig vascular tissues to noradrenaline, isoprenaline and perivascular nerve stimulation were investigated. 2 Amosulalol (10 −10 −10 −5 m ) did not alter the resting membrane potential of smooth muscle cells of the mesenteric artery, the mesenteric vein, the main pulmonary artery and the portal vein. 3 In the mesenteric artery, main pulmonary artery and portal vein, but not in the mesenteric vein, membrane depolarizations produced by noradrenaline were antagonized by amosulalol. 4 In the portal vein, membrane hyperpolarizations produced by isoprenaline were antagonized by amosulalol. 5 In the mesenteric artery, amosulalol (over 10 −6 m ) enhanced the amplitude of excitatory junction potentials (e.j.ps) produced by perivascular nerve stimulation. 6 Amosulalol antagonized the noradrenaline‐induced decrease in the e.j.p. amplitude; this effect was much weaker than that of phentolamine. Amosulalol also antagonized the isoprenaline‐induced enhancement of the e.j.p. amplitude. 7 In the mesenteric vein, the slow depolarizations produced by perivascular nerve stimulation were depressed by amosulalol (over 10 −6 m ), but the effect was much weaker than that of prazosin, yohimbine or phentolamine. 8 Actions of amosulalol on electrical properties of vascular tissues can be summarized as follows: amosulalol blocks α 1 ‐ and β‐adrenoceptors. It also blocks α 2 ‐adrenoceptors, though weakly.