Haemodynamic effects of tetrandrine on conscious rats
Abstract
Haemodynamic study of tetrandrine (Tet) in conscious rats showed that 15 mg/kg iv lowered the blood pressure (BP), LVSP, ±dp/dtmal，and (dP/dt) P-1. The degrees of diminutions were nearly equal to that of BP during the initial period, while the LVEDP was elevated. But all these parameters (except-dp/dtmax) recovered gradually and earlier than BP, and the LVEDP decreased to a level slightly lower than that of its control. These results indicate that the hypotensive action of Tet is mainly due to its inhibition of cardiac contractility at the early period, while in the later stage due to vasodilation.
The HR was slowed down abruptly followed by a reflex acceleration and then a gradual but sustained decrease in HR supervened with iv Tet.
When large dose (40 mg/kg) of Tet iv caused a cardiac standstill with the R wave of ECG persisted for a few minutes; i. e., an excitation-contraction decoupling occurred as that found in isolated myocardial preparation with verapamil and Tet.
Keywords:
The HR was slowed down abruptly followed by a reflex acceleration and then a gradual but sustained decrease in HR supervened with iv Tet.
When large dose (40 mg/kg) of Tet iv caused a cardiac standstill with the R wave of ECG persisted for a few minutes; i. e., an excitation-contraction decoupling occurred as that found in isolated myocardial preparation with verapamil and Tet.