PROCAINE-INDUCED POSITIVE CHRONOTROPIC AND INOTROPIC RESPONSES OF ISOLATED, BLOOD-PERFUSED DOG ATRIUM

  • 1 January 1977
    • journal article
    • research article
    • Vol. 225  (1) , 104-113
Abstract
In the isolated, blood-perfused canine atrium preparations, procaine given into the cannulated sinus node artery induced frequently significantly positive chronotropic and inotropic effects at a dose level of 30-1000 .mu.g. Above a dose of 100 .mu.g, initially brief negative chronotropic and inotropic effects were usually observed. Procaine-induced negative effects were not blocked by an adequate dose level of atropine. Procaine-induced positive effects were inhibited by treatment with propranolol but not modified by tetrodotoxin or desmethylimipramine. Procaine suppressed acetylcholine-induced negative chronotropic and inotropic effects, but procaine did not block norepinephrine-induced positive inotropic and chronotropic effects. Procaine may have sympathomimetic and atropine-like properties.