Higenamine was isolated originally from Aconiti tuber from Aconitum species and recently Higenamine was synthesized. The purpose of this study is to investigate the adrenergic effect of Higenamine on rabbit cardiovascular system. Blood pressure, cardic output, systemic vascular resistance and heart rate were measured after intravenous injection of Higenamine(2-100microg/kg/min). The effects of Higenamine were compared with those of other sympathomimetic drugs. The changes in the cardiovascular systems after pretreatment with Propranolol, Atenolol and Hexamethonium were also studied. The following results were obtained. 1) Higenamine increased the cardic output and the heart rate and decreased the blood pressure and the systemic vascular resistance. Those changes were dose-dependent. The duration of action of Higenamine was 5 to 8 minutes. 2) The effects of Higenamine were similar to those of Isoproterenol. The amount of Higenamine was more than 100 times the required amount of Isoproterenol in order to obtain the same casdiovascular effects. 3) The effects of Higenamine were blocked by Propranolol, The increase of cardic output and heart rate were blocked by Hexamethonium. Higenamine has stimulating action on beta1 and beta2 receptors. But Higenamine is much less potent than Isoproterenol.
Aconitum ; Adrenergic Agents* ; Atenolol ; Blood Pressure ; Cardiovascular System* ; Heart Rate ; Hexamethonium ; Injections, Intravenous ; Isoproterenol ; Propranolol ; Sympathomimetics ; Vascular Resistance