EFFECTS OF PANAX NOTOGINSENG SAPONINS ON MYOCARDIAL ADENOSINE-TRIPHOSPHATASE

Effects of total Panax notogin seng saponins (PNS) and Panax notoginse ng saponin monomers Rb-1 and Rg(1) (Rb-1, Rg(1)) on total ATPase and N a-(+)-K-(+)-exchanging ATPase of guinea pig heart were studied. It was found that PNS inhibited the total myocardial ATPase, but had no sign ificant effect on the myocardial Na-(+)-K-(+)-exchanging ATPase. The t otal ATPase was inhibited by Rg(1), and more clearly by Rb-1. The auto maticity and contractility of isolated guinea pig atria were inhibited by Rb-1. Rg(1) decreased the spontaneous frequency of isolated guinea pig right atrium, but not markedly the contractility of the left atri um. These results demonstrate that Rb-1 is the main ingredient in PNS.