CARDIOVASCULAR EFFECTS OF OBLONGINE CHLORIDE, AN ALKALOID FROM LEONTICE LEONTOPETALUM, IN THE ANESTHETIZED GUINEA-PIG

The effects of(-)oblongine chloride, a quaternary alkaloid from Leonti ce leontopetalum on blood pressure, heart rate and blood dow of the an aesthetized guinea-pig were studied, At doses ranging from 0.5 mg/kg t o 30 mg/kg, i.v., oblongine chloride caused a dose-dependent reduction of systolic and diastolic blood pressure, These doses were associated with an increase in heart rate, Propranolol (5 mg/kg) failed to block the effects of oblongine chloride on systolic and diastolic blood pre ssure but significantly reduced the increase in heart rate observed wi th low doses (0.5-6 mg/kg) of oblongine chloride, In doses ranging fro m 0.05 mg/kg to 0.5 mg/kg, oblongine chloride caused a small increase in blood Bow, Larger doses (1.5, 4.5, 15 and 30 mg/kg) caused an initi al decrease followed by an increase of blood flow, The net effect of c umulative doses was an increase in blood flow over the control value, These observations suggest that oblongine chloride may have potential haemodynamic effects and that these effects are not mediated by beta-a drenergic receptor stimulation.