Studies on the calcium antagonistic action of tetrandrine: I. Effects of tetrandrine on the isolated guinea pig atrium

Abstract

Tetrandrine (T), an alkaloid isolated from the root of Stephania tetrandra S. Moore, possessed an antihypertensive, antianginal and antiarrhythmogenic effect.

This paper studied the direct influence of tetrandrine upon the contractility, automaticity, excitability and refractory period of isolated atrium of guinea pigs.

1.	Tetrandrine 32 uM decreased the contractility, ±dT/dt max and automaticity and prolonged the functional refractory period (FRP), but exerted no influence upon its excitability.
2.	The decrease in automaticity and prolongation of refractory period were thought to be ascribed to its antiarrhythmic action.
3.	The negative inotropic and automaticitic effects suggested that tetrandrine might be antagonistic to Ca++.

Keywords

tetrandrine / guinea pig atrium / calcium antagonist

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