or saline and then administered cocaine (10 mg/kg, i.v. bolus). Coronary blood flow, heart rate, mean arterial pressure, and the first derivation of left ventricular pressure (dP/dt) were measured at baseline, 2 minutes, and 15 minutes after cocaine administration. Nifedipine pretreatment prevented the early cocaine-induced decrease in coronary blood flow and improved left ventricular dP/dt com...