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AGONIST/ANTAGONIST ACTIVITY OF ERGOCRISTINE AT ALPHA‐ADRENOCEPTORS IN THE RAT
Author(s) -
ROQUEBERT J.,
DEMICHEL P.
Publication year - 1987
Publication title -
fundamental and clinical pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.655
H-Index - 73
eISSN - 1472-8206
pISSN - 0767-3981
DOI - 10.1111/j.1472-8206.1987.tb00542.x
Subject(s) - yohimbine , prazosin , vas deferens , phenylephrine , medicine , endocrinology , rauwolscine , antagonist , alpha (finance) , agonist , postsynaptic potential , stimulation , clonidine , chemistry , biology , receptor , blood pressure , construct validity , nursing , patient satisfaction
Summary—1 The action of ergocristine at α‐adrenoceptors was studied in vivo in the pithed rat, and in vitro on the rat isolated vas deferens. 2 In the pithed rat, the pressor response to ergocristine was reduced competitively by yohimbine, but not by prazosin. 3 Ergocristine decreased the tachycardia elicited by electrical stimulation of the cardioaccelerator sympathetic nerves, this effect being antagonized by yohimbine. 4 At postsynaptic α 1 ‐adrenoceptors, on the vas deferens of the rat, ergocristine antagonized the contraction induced by phenylephrine in a competitive manner (p A 2 = 7.85). 5 These results show that vasoconstriction due to ergocristine is mediated by α 2 ‐adrenoceptors and that, in the rat, ergocristine acts as an α 2 ‐adrenoceptors agonist, and an α 1 ‐adrenoceptors antagonist.