EFFECTS OF ALINIDINE (ST 567) ON BARORECEPTOR-HEART RATE REFLEXES AND ITS INTERACTIONS WITH CLONIDINE ON THE BAROREFLEX AND ON THE SYMPATHETIC TERMINALS OF THE ISOLATED ATRIUM

Abstract

Alinidine (ST 567), an N-allyl derivative of clonidine, slowed the heart rate of conscious rabbits by 41 +/- 2.3 (S.E.D.) b/min and reduced mean arterial pressure (MAP) by 6.4 +/- 1.4 mmHg (P less than 0.001). The cardiac slowing was considered to be a direct effect in agreement with previous findings by others, since it was present in rabbits without functioning autonomic nerves, but the fall in blood pressure did not occur in these animals. Alinidine produced no significant changes in the reflex tachycardia response evoked by infusing nitroprusside, or in the pressure-related parameters of the MAP-heart period (HP) curve of the baroreceptor-heart rate reflex (i.e. HP range, gain, or median..