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CHARACTERIZATION OF VASCULAR HISTAMINE RECEPTORS IN THE RAT
Author(s) -
POWELL JAMES R.,
SHAMEL L. BLAIR
Publication year - 1979
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.1476-5381.1979.tb13688.x
Subject(s) - metiamide , mepyramine , histamine , vasodilation , agonist , histamine h2 receptor , histamine h1 receptor , endocrinology , medicine , histamine receptor , receptor , vascular smooth muscle , chemistry , pharmacology , antagonist , smooth muscle
1 In the rat the decrease in blood pressure caused by histamine involves activation of both H 1 ‐ and H 2 ‐receptors. Since arterial pressure measurements alone do not permit the separation of responses into cardiac and vascular components, the following experiments were undertaken to study vascular histamine receptors. 2 Vascular responses were studied in the autoperfused hindquarters of anaesthetized rats. Intra‐arterial histamine caused vasodilatation which was only partially attenuated by treatment with mepyramine, an H 1 ‐receptor antagonist. Treatment with metiamide, the H 2 ‐receptor antagonist, did not affect vasodilatation caused by histamine but did attenuate vasodilatation which persisted after mepyramine. 3 Intra‐arterial 4‐methylhistamine, an H 2 ‐receptor agonist, caused vasodilatation which was reduced by metiamide. The H 1 ‐receptor agonist, 2‐(2‐pyridyl)ethylamine also caused vasodilatation which was blocked by mepyramine. 4 It is concluded that in the rat, histamine causes vasodilatation mediated by both H 1 ‐ and H 2 ‐receptors.