Effect of dl-praeruptorin A on calcium current in ventricular cells of guinea pig

With patch clamp technic (whole cell recording), the effect of dl-praeruptorin A (Pra), an ingredient of Peucedanum praeruptorum Dunn on calcium current (ICa) in the single ventricular cells of guinea pig was studied. Results showed that under Cs/Cs condition, when the holding potential was -40 mV and in the presence of Pra (1, 10, 100 mumol.L-1), ICa was decreased dose-dependently from 2.02 +/- 0.24, 2.00 +/- 0.12, 2.12 +/- 0.33 nA (control) to 1.60 +/- 0.24, 1.32 +/- 0.08, 1.16 +/- 0.43 nA, respectively, and their inhibitory rates were 21%, 33.5%, 45%, respectively. The current-voltage relation curve showed that the reversal potential of ICa was +60 mV; the potential producing peak value of ICa was about 0 mV. The results indicated that Pra had a Ca2+ channel blocking effect.