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The pharmacology of the cholinoceptor in muscle preparations of Ascaris lumbricoides var. suum
Author(s) -
NATOFF I. L.
Publication year - 1969
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.1476-5381.1969.tb09542.x
Subject(s) - pharmacology , acetylcholine , chemistry , muscarine , methiodide , nicotinic agonist , hexamethonium , atropine , nicotine , mecamylamine , muscarinic acetylcholine receptor , endocrinology , medicine , biochemistry , receptor
1 . The preparation of a muscle strip of Ascaris lumbricoides for the study of the effect of drugs in vitro is described. 2 . Stimulant drugs which are classified as nicotine‐like in mammalian pharmacology increased the isometric tension of this preparation. These drugs were, in descending order of potency: dimethylphenylpiperazinium, nicotine, acetylcholine, carbachol, decamethonium and pyridine‐2‐aldoxime methiodide. 3 . Muscarine‐like drugs (oxotremorine, methacholine, pilocarpine) had no activity. 4 . Potassium and barium ions stimulated the tissue, while the anti‐cholin‐esterases, dichlorvos and eserine, increased the resting tension of the preparation and potentiated the responses to acetylcholine. 5 . Adrenaline neither stimulated the tissue nor affected the responses to nicotine‐like drugs. 6 . The relative potency of several blocking agents which antagonize the responses to nicotine‐like drugs was assayed. These blocking agents were, in descending order of potency: mecamylamine, (+)‐tubocurarine, hexamethonium, atropine and piperazine. Acetylcholine, dimethylphenylpiperazinium and pyridine‐2‐aldoxime methiodide apparently act on a common receptor, for each blocking agent had a similar molar inhibitory concentration against these stimulants. 7 . It is concluded that the cholinoceptor in muscle preparations of Ascaris lumbricoides is pharmacologically similar to that of the mammalian autonomic ganglion.