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EFFECTS OF Gymnodinium breve TOXIN ON THE SMOOTH MUSCLE PREPARATION OF GUINEA‐PIG ILEUM
Author(s) -
GRUNFELD Y.,
SPIEGELSTEIN M.Y.
Publication year - 1974
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.1476-5381.1974.tb09633.x
Subject(s) - tetrodotoxin , hexamethonium , ileum , tachyphylaxis , neurotoxin , cholinergic , guinea pig , mepyramine , marine toxin , biology , atropine , toxin , stimulation , endocrinology , medicine , acetylcholine , chemistry , biochemistry , antagonist , receptor
1 The effects of Gymnodinium breve neurotoxin (GT) on smooth muscles were studied using the guinea‐pig isolated ileum. 2 The toxin caused strong spasmogenic effects at 1–4 μg/ml, characterized by prolonged tonic contraction with superimposed pronounced pendular movements. Tachyphylaxis was observed upon administration of successive doses. 3 Atropine blocked the contractile response elicited by GT, whereas mepyramine and hexamethonium failed to do so. These findings tentatively suggested a cholinergic involvement at a post‐ganglionic site of action. 4 In the presence of tetrodotoxin the effects of GT were abolished, excluding direct action of the toxin on the smooth muscle. 5 It is concluded that GT exerts its spasmogenic effects through stimulation of the post‐ganglionic cholinergic nerve fibres.