STUDIES ON DRUGS FOR TREATMENT OF HYPERTENSION,Ⅶ.CARDIAC AND CEREBRAL HEMODYNAMIC EFFECTS OF THE ALKALOID FROM THE ROOT OF RAUWOLFIA VERTICILLATA FROM HAINANDAO

The cardiac output of anesthetized dogs was determined by direct Fick's principle. Intravenous injections of the alkaloid 0.5 mg/kg produced hypotension, tachycardia, and a marked reduction of the total peripheral resistance. Though the stroke volume became less, the minute cardiac output remained undiminished. Hence, the hypotensive effect was chiefly due to vasodilatation. Repeated administrations resulted in marked tachyphylaxis. The cerebral circulation of rabbits, anesthetized or conscious, was measured with a bubble flowmeter. Intravenous injections of 5 mg/kg resulted in a hypotension during which a slowing down of the cerebral blood flow was observed.