Vasodilator effects of cepharanthine, a biscoclaurine alkaloid, on cutaneous microcirculation in the rabbit.

Cutaneous microcirculatory responses to intravenous administration of cepharanthine (CT), a biscoclaurine alkaloid, isolated from Stephania cepharantha, were studied in a transparent round chamber installed in a rabbit ear, under conscious conditions. Vital-microscopic observations were made visually with a microscope-closed TV system and microphotoelectric plethysmography. Following the CT administration in doses of 1.0 and 3.0 mg/kg, an enhancement of rhythmic perfusion of microvascular blood due to vasomotion was developed for a period of 1 h or longer, although no appreciable change was observed following CT administration at 10.0 mg/kg. The microvascular dilator effect of CT appeared to have no direct association with systemic hemodynamics, based on the additional measurements of heart rate, blood pressure, carotid blood flow and auricular arterial blood flow.