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Biphasic non‐adrenergic, non‐cholinergic relaxations of the mouse anococcygeus muscle
Author(s) -
Gibson A.,
Yu O.
Publication year - 1983
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.1476-5381.1983.tb11036.x
Subject(s) - carbachol , apamin , tetrodotoxin , chemistry , endocrinology , stimulation , cholinergic , medicine , adrenergic , propranolol , neostigmine , muscle relaxation , atropine , biology , potassium channel , biochemistry , receptor
1 Trains of field stimulation of 60 s duration caused a biphasic relaxation of carbachol (50 μ m )‐induced tone in the mouse anococcygeus. The optimal pulse frequency and width were 10 Hz and 1 ms respectively. 2 Tetrodotoxin (31, 124, and 310 n m ) caused a dose‐dependent reduction in the magnitude of both phases. Neither phase was affected by (±)‐propranolol (1 μ m ), neostigmine (1 μ m ), (+)‐tubocurarine (100 μ m ), or apamin (500 n m ). Biphasic relaxations were observed in muscles from 6‐hydroxydopamine pretreated mice. 3 Haemolysed blood (10, 40, and 100 μ m ) reduced the magnitude of the first phase of nerve‐induced relaxation to a greater extent than the second. This effect was reversible. 4 Following a prolonged train of inhibitory nerve stimulation (10 Hz; 10 min) the magnitude of the first phase was reduced only slightly, but the second markedly. 5 The possible relationships between the biphasic relaxation to field stimulation and putative non‐adrenergic, non‐cholinergic transmitters in the mouse anococcygeus are discussed.