RESUMO
Objective:To study the e ects of anthopleurin-Q(AP-Q) on potassium currents of ventricular myocytes in rats and guinea pig.Methods:The ventricular cells of guinea pigs and S.D.rats were obtained by enzymatic method.Whole cell patch clamp technique was used to record potassium currents,including transient outward potassium currents(Ito),delayed recti er potassium current(IK) and inward recti er potassium current(IK1).Results:AP-Q 3-100 nmol/L blocked Ito in a concentration-dependent manner with an EC50 value of 10.5 nmol/L.With +50 mV depolarized pulse and 10nmol/LAP-Q,the Ito increased from(13.3?3.4)pA/pFto(19.46?4.3)pA/pF.AP-Q 0.1-100 nmol/Lincreased IK and tail current(IK tail) in a concentration-dependent manner with EC50 value of 4.7 nmol/Land 5.0 nmol/L,respectively.AP-Q 1 pmol/L-100 nmol/Lincrease IK1 in a concentration-dependent manner with EC50 value of 0.2 nmol/L.Conclusion:Augmented e ect of AP-Q on Ito,IK and IK1 may partly explain its e ects of shortening APD and increasing absolute value of RP.