Cardiorespiratory and metabolic actions of dopamine in dogs and sheep

A continuous intravenous infusion of 7.5 μg/kg/min of dopamine in dogs failed to produce any measurable circulatory, respiratory or metabolic changes. In sheep the same dose caused a rise in cardiac output, fall in systemic arterial resistance and an increase in arterial P CO 2 ; ventilation, arterial lactate, pyruvate and glucose concentrations remained unaffected. In sheep subjected to α + β adrenergic receptor blockade dopamine only vaused a fail in systemic arterial pressure: the rise in cardiac output was virtually abolished.