Effect of root saponins of Panax notoginseng on different voltage-dependent calcium and potassium ion channels / 中国药理学与毒理学杂志

ABSTRACT

OBJECTIVE To investigate the effect of root saponins of Panax notoginseng(RPNS) on different voltage-dependent calcium and potassium ion channels. METHODS By using the two-elec?trode voltage clamp (TEVC), the effect of RPNS 0.01, 0.06, 0.1, 0.6, 1 and 4 g · L- 1 was investigated on Cav1.2,and the effect of RPNS 1 g · L-1 was evaluated on Cav2.1,Cav2.2,Cav3.1, KCNH2,KCNQ1,KCNQ1/KCNE1 and BK channel. All the ion channels examined were expressed in Xenopus laevis oocytes. RESULTS TEVC suggested that the effect of RPNS on Cav1.2 exhibited the concentration-response relationship and its EC50 was 0.048 g · L-1. Compared with cell control,TEVC also showed that RPNS 1 g·L-1 had obviously inhibitory effect on Cav1.2,Cav2.2 and Cav3.1,and the inhibitory rate of RPNS 1 g · L-1 on the peak current of Cav1.2,Cav2.2 and Cav3.1 was(57.1 ± 8.6)%, (17.2 ± 0.7)% and(50.2 ± 7.7)%(P<0.01),respectively. RPNS 1 g · L-1 had obviously activated effect on BK channel,and the activated rate of RPNS 1 g·L-1 on the peak current of BK channel was(37.9± 2.7)%(P<0.01). RPNS 1 g·L-1 showed no significant effect on Cav2.1,KCNH2,KCNQ1 and KCNQ1/KCNE1. CONCLUSION RPNS may effectively inhibit Cav1.2 and Cav3.1,activate BK channel,but have little effect on Cav2.1,Cav2.2,KCNH2,KCNQ1 and KCNQ1/KCNE1.