THE BLOCKING EFFECT OF HYPERIN 0N THE INW ARD FLOW OF CAI IUM ION

Hyperin(Hyp)was shown to inhibit the positive inotropic action of calcium ion onthe isolated papillary muscles and shift the dose response curve of calcium ion to the right.As a plotlg(x一1)us一lg(B)resulted in straight lines with slopes of一0.625.On the action potentials ofguinea pig myocardical cells,Hyp markedly decreased the duration of plateau of action potentials(APD_20%)but did not influence the APD_100%, RP,APA,OS and Vmax.In the atrium preparationsof mice, Hyp significantly inhibited influx of ⁴⁵Ca induced by high K⁺,All findings indicate that Hypcan inhibit the in ward flow of calcium ion.