Haemodynamic effect of the venom of Bitis Gabonica in the dog.

Intravenous injection of 0.125 mg/kg of venom of Bitis Gabonica in the anaesthetized dog produces an immediate but reversible decrease in total peripheral and coronary vascular resistance. Stroke volume show a transient increase followed by an irreversible reduction. A second dose of 0.25 mg/kg produces the same effect on total peripheral and coronary vascular resistance, but furtherly reduces the stroke volume. A third dose of 0.50 mg/kg kills the animal after an extreme reduction of the stroke volume. The progressive decrease of the stroke volume might be due to a failure of the ventricle to relax, whereas its transient increase immediately after the injection depends on the abrupt fall of the total peripheral resistance.