Effects of matrine on action potentials and contractile force in guinea pig papillary muscles / 中国药理学通报

ABSTRACT

AIM To study the effects of matrine (Ma) on the action potential and contractile force in guinea pig papillary muscles. METHODS Conventional microelectrode technique was used to record the fast action potentials (FAP) and slow action potentials (SAP) induced by histamine and BaCl_2 of guinea pig papillary muscles. RESULTS Ma 10,25,50 ?mol?L -1 dose-dependently prolonged the action potential duration at 50%, 90% repolarization (APD_ 50 , APD_ 90 ) and effective refractory period (ERP) of FAP, and lengthened the APD_ 50 , APD_ 90 of SAP induced by histamine and BaCl_2 when perfused with KCl 25 mmol?L -1 Tyrode's solution. The maximal upstroke velocity (V_ max ) of FAP, SAP and contractile force (Fc) were not affected by matrine 10,25,50 ?mol?L -1 . CONCLUSION It was suggested that Matrine could block K + channels in the myocardium.-