Influence of the sympathomimetic activity of oxprenolol on haemodynamics in the anaesthetized dog.

In anaesthetized, artificially respirated mongrel dogs, the intravenous infusion of oxprenolol (0.3 mg and 1 mg/kg over 10 minutes) led to an increase in heart rate and cardiac output. Blood pressure in the pulmonary capillaries and right atrium, and vascular resistance were reduced. The pressure in the aorta was transiently decreased. Infusion of propranolol in the same doses was followed by a decrease in heart rate and cardiac output. The calculated peripheral resistances, pulmonary capillary pressure and right-atrial pressure increased slightly. Pressure in the aorta diminished slightly. In the light of the present results, it is evident that the intrinsic sympathomimetic activity of oxprenolol has a significant bearing on its haemodynamic effects in the anaesthetized dog.