Blocking effects of heteroclitin D and gomisin J on L-type calcium channels in ventricular cells of guinea pig

AIM: To study the effects of heteroclitin D (HD) and gomisin J (GJ), two lignans from Kadsura medicinal plants, on L-type calcium channels in ventricular cells of guinea pig. METHODS: The calcium currents were measured by whole-cell patch-clamp recording technique. RESULTS: HD 1 and 10 μmol/L decreased the L-type calcium current from (770 ± 155) to (482 ± 104) and (384 ± 85) pA, respectively. GJ 10 μmol/L inhibited calcium current from (822 ± 169) to (436 ± 143) pA. Neither HD nor GJ affected the steady-state activation curve. But they had impact on steady-state inactivation curve. HD 10 μmol/L changed the half inactivation voltage (V_0.5) from -22.7 to - 40.9 mV, and slope factor (κ) from 10.2 to 20.6 (n = 4 cells from 3 guinea pigs, P < 0.05). GJ 10 μmol/L changed the V_0.5 from -17.7 to -33.3 mV, and κ from 15.9 to 27.8 (n = 5 cells from 3 guinea pigs, P < 0.05). CONCLUSION: HD and GJ inhibited L-type calcium channels.