Article: PDF OnlyFlaim Stephen F.; Stranieri, Maria T.; Mathiasen, Joanne R.Journal of Cardiovascular Pharmacology: March 1988 - p 363-372 Free Abstract Summary The purpose of this study was to characterize he cardiocirculatory effects of bepridil hydrochloride BP) in the normal, conscious rat. Animals were instrumented under halothane anesthesia for right atrial, left perticular, arterial, and venous pressure recordings. The adioactive-microsphere technique was used to measure Regional blood flow and cardiac output before (control) and during intravenous (i.v.) infusion of either BP at three dosage levels (3.0, 6.0, 12.0 mg/kg) or vehicle (VH) it infusion rates matching those of the BP protocol 0.0408 ml/min). The predominant effects of BP (cumulative dose = 9.0 mg/kg i.v.) in the conscious rat were reluced coronary vascular resistance and heart rate. BP showed selectivity for the coronary circulation since systemic vascular resistance was not significantly reduced until a cumulative i.v. dosage of 21.0 mg/kg was administered. BP had few effects on other regions of the peripheral circulation. BP (21 mg/kg) reduced blood flow and increased vascular resistance in the arterial circulations of four of six skeletal muscles studied although opposite effects occurred in two of six muscles studied. BP had no significant effect on blood flow or vascular resistance in the other major arterial circulations. The results of this study show that BP is a selective coronary vasodilator that also reduces the primary indices of myocardial oxygen demand. These results suggest that the clinical therapeutic antianginal efficacy of BP occurs through a combined effect to increase myocardial oxygen supply and to reduce myocardial oxygen demand. © Lippincott-Raven Publishers.