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Aspects of the pharmacology of a new anthelmintic: pyrantel
Author(s) -
AUBRY M. L.,
COWELL PAULINE,
DAVEY M. J.,
SHEVDE S.
Publication year - 1970
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.1476-5381.1970.tb08521.x
Subject(s) - pyrantel , pharmacology , acetylcholine , biology , muscle relaxation , anthelmintic , anatomy , anesthesia , chemistry , endocrinology , medicine , ecology
Summary1 . The pharmacological properties of an anthelmintic, pyrantel, and some of its analogues have been described and compared with piperazine in a variety of vertebrate and helminth preparations. 2 . Pyrantel and its analogues in common with nicotine and decamethonium cause spastic paralysis in chicks and contracture of the chick semispinalis and toad rectus abdominis muscles. 3 . In the soleus and anterior tibialis muscles of the cat, pyrantel in large amounts caused a short‐lived neuromuscular block that was preceded by initial depolarization. 4 . In preparations from cat and rat, pyrantel showed properties common to both competitive and depolarizing neuromuscular blocking drugs. 5 . Pyrantel blocked the contracture evoked by transmural stimulation and caused a marked contracture of the worm. Piperazine caused a gradually developing reduction in the responses to transmural stimulation and no contracture. 6 . Pyrantel and its analogues caused a slowly developing contracture of strip preparations of Ascaris , being more than 100 times more active than acetylcholine in this respect. Piperazine caused a relaxation of Ascaris strip preparations and in common with (+)‐tubocurarine blocked the responses to acetylcholine and pyrantel analogues on this preparation. 7 . Pyrantel caused depolarization and increased spike discharge frequency in single muscle cells of Ascaris , these changes being accompanied by increase in tension. Piperazine, on the other hand, caused hyperpolarization and reduction in spike discharge frequency and relaxation, and antagonized the effects of pyrantel.