EFFECTS OF ETHANOL AND ACETALDEHYDE ON THE ISOLATED, BLOOD-PERFUSED CANINE ATRIUM

  • 1 January 1979
    • journal article
    • research article
    • Vol. 239  (1) , 109-120
Abstract
In the isolated, blood-perfused canine atrium preparations, ethanol injected into the cannulated sinus node artery consistently produced dose-dependently negative inotropic effects at a dose range of 0.03-1 mmol and negative chronotropic effects starting from 0.1 mmol. Ethanol-induced negative inotropic and chronotropic responses were not blocked by atropine. When acetaldehyde was given into the sinus node artery, positive inotropic and chronotropic effects were dose-relatedly produced from 0.1-30 .mu.mol. Acetaldehyde-induced positive inotropic and chronotropic effects were inhibited by treatment with propranolol. These positive effects were not suppressed by imipramine or tetrodotoxin, but imipramine inhibited tyramine-induced actions and tetrodotoxin suppressed acetylcholine-induced positive chronotropic and inotropic effects in atropine-treated preparations. Apparently ethanol has direct depressant properties on pacemaker and contractile activities, and that acetaldehyde has stimulating properties through adrenergic .beta.-receptors but neither through tyramine-like action nor nerve excitation.