Effects of histamine on atrial and ventricular contractility in the canine isovolumic heart

Abstract

The effects of intracoronary administration of histamine on atrial and ventricular contractility were determined in a paced canine isovolumic heart preparation. Contractility was assessed by recording the pressure developed in saline-filled balloons placed in each of the four cardiac chambers. At doses above 0.1 mg and up to 100 mg histamine produced dose-related positive inotropic responses in all chambers. These were preceded by transient negative effects. The positive responses were not affected by a combination of H1 and H2 receptor antagonists antazoline and cimetidine but were almost completely abolished by the beta adrenoceptor blocker timolol. The negative responses were uninfluenced by either treatment. It was concluded that, in the canine isovolumic heart not subjected to complicating chronotropic and extracardiac factors, moderate doses of histamine are devoid of inotropic effects. Higher doses do produce myocardial stimulation, not mediated by histamine receptors, but probably due to norepinephrine release. These responses are preceded by transient non-specific depressant effects.

The Roles of Cardiovascular H2-Histamine Receptors Under Normal and Pathophysiological Conditions

“…In canine studies, Chiba injected histamine, 0.3–100 μg, into the cannulated sinus node artery of the isolated right atrium which was blood perfused by a living donor dog (the sex of the dogs was not published: Chiba, 1976 ). In living anaesthetized dogs on bypass, histamine 0.1–100 mg was intracoronarilly applied ( Vidrio and Priola, 1990 ). In dog lung preparations with blood obtained from donor hearts, histamine (calculated as free base) was intravenously given at doses of 0.1–10 mg ( Flacke et al , 1967 ).…”