Low dose dopamine (1-2 mcg/kg) result in
At low concentrations, the primary interaction of dopamine is with vascular D1 receptors, especially in the renal, mesenteric, and coronary beds-leads to vasodilation Higher concentrations, dopamine exes a positive inotropic effect on the myocardium, acting on beta-1 adrenergic receptors. At more than 10 mcg/kg/min rate of infusion, dopamine can stimulate alpha 1 receptors leading to peripheral vasoconstriction Dopamine also causes the release of norepinephrine from nerve terminals, which contributes to its effects on the hea. DOSE DEPENDENT EFFECTS OF DOPAMINE Dose Rate Receptors stimulated Major action Low dose 1-2 mcg/kg/min D1 Renal vasodilation Intermediate dose 2-10 mcg/kg/min D1 & Beta 1 Cardiac stimulation High dose > 10 mcg/kg/min D1, Beta 1 and Alpha 1 Vasoconstriction
Sympathetic System
Constriction of renal vasculature
Dilatation of renal vasculature
Increase in cardiac output
CNS stimulation
Dilatation of renal vasculature