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Bretylium potentiation of the contractor responses of isolated rabbit aortic strips to potassium and tyramine
Author(s) -
KURAHASHI K.,
SHIBATA S.
Publication year - 1971
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.1476-5381.1971.tb07170.x
Subject(s) - bretylium , tyramine , potassium , long term potentiation , chemistry , pharmacology , endocrinology , medicine , adrenergic , biochemistry , receptor , organic chemistry
Summary1 Pretreatment of rabbit aortic strips with bretylium potentiated the contractor response to potassium and tyramine but not to noradrenaline. On the other hand, such pretreatment inhibited the response to nicotine. 2 Even in reserpinized or cold stored aortic strips, pretreatment with bretylium enhanced the contractor response to potassium and tyramine. 3 Pretreatment of fresh, reserpinized, or cold stored aortic strips with pheniprazine potentiated the contractor response to potassium and tyramine. 4 Pretreatment of aortic strips with bretylium or pheniprazine did not potentiate the response to 5‐hydroxytryptamine (5‐HT). 5 The results indicate that both bretylium and pheniprazine potentiate the action of tyramine and potassium, not by presynaptic mechanisms, but by postsynaptic action, causing an increase in the sensitivity of the effector cells to the stimulants.