Cardiovascular effects of pennogenin tetraglycoside (Tg) extracted from Paris quadrifolia LINN. were investigated in mice, bull-frogs and rabbits. The Tg doses of 1-10 mg/kg (i.v.) produced a fall in blood pressure. The fall in blood pressure was not affected by the pretreatment with atropine and physostigmine. On the isolated bull-frog heart preparation in Yagi-Hartung's method, Tg caused a marked increase in the amplitude without changes in the heart rate at a concentration of 3.3×10-6 g/ml. At a concentration of 3.3×10-5 g/ml, Tg caused a slight increase in the amplitude with a marked augmentation in the tonus. On the cardiograph method in rabbits', Tg at a dose of 0.5 mg/kg (i.v.) produced a fall in blood pressure, an increase in the amplitude and tonus in the heart and an inhibition in respiration. These results suggest that Tg has a stimulating action on cardiac system.
