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EFFECTS OF 5‐HYDROXYTRYPTAMINE ON CANINE ISOLATED CORONARY ARTERIES
Author(s) -
PORQUET MARIEFRANCE,
POURRIAS BERNARD,
SANTAMARIA RAPHAEL
Publication year - 1982
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.1476-5381.1982.tb08787.x
Subject(s) - methysergide , coronary arteries , phentolamine , medicine , circumflex , serotonin , endocrinology , chemistry , cardiology , receptor , artery
1 The effects of 5‐hydroxytryptamine (5‐HT) were studied in vitro on proximal and distal portions of canine interventricular and circumflex coronary arterial strips. 5‐HT produced concentration‐related contractions in the proximal portion whether contracted previously with KCl or not. These responses were still present after either chemical sympathetic denervation or release of noradrenaline induced by K + ‐free salt solution. In contrast, the distal portions of coronary arteries did not respond to 5‐HT. 2 Concentration‐response curves to 5‐HT exhibited a classical hyperbolic shape with a calculated Hill‐coefficient of approximately 1. 3 Methysergide and phentolamine but not morphine shifted to the right and depressed the maximum of the dose‐response curves to 5‐HT. 4 It is concluded that the contractions produced by 5‐HT in the proximal portion of the interventricular and circumflex coronary arteries are not due to the release of endogenous noradrenaline. The vessels appear to possess separate receptors for 5‐HT and noradrenaline and the 5‐HT responses belong to neither the M nor the D type.