Abstract
The actions of bradykinin and the influences of several drugs on them were investigated on the isolated spontaneous beating and electrically driven atria of guinea pigs.
Results : (1) Bradykinin produced an increase of heart rate and myocardial contractile force. These actions were dose dependent. 2) The positive chronotropic and inotropic actions of bradykinin were not influenced by reserpinization or by administering α- and β-adrenergic blocking agents. Therefore, bradykinin was considered to possess a direc cardiac stimulating action. 3) Homochlorcyclizine, pyridinolcarbamate and diphenhydramine depressed the positive chronotropic action significantly, but did not affect the positive inotropic action of bradykinin. 4) Histamine did not relate to the cardiac action of bradykinin.
