Blocking effects of heteroclitin D and gomisin J on L-type calcium channels in ventricular cells of guinea pig.
OBJECTIVE
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 mumol/L decreased the L-type calcium current from (770 +/- 155) to (482 +/- 104) and (384 +/- 85) pA, respectively. GJ 10 mumol/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 mumol/L changed the half inactivation voltage (V0.5) from -22.7 to -40.9 mV, and slope factor (kappa) from 10.2 to 20.6 (n = 4 cells from 3 guinea pigs, P < 0.05). GJ 10 mumol/L changed the V0.5 from -17.7 to -33.3 mV, and kappa from 15.9 to 27.8 (n = 5 cells from 3 guinea pigs, P < 0.05).


CONCLUSIONS
HD and GJ inhibited L-type calcium channels.
Zhang
X M
XM
Department of Pharmacology, Shanghai Medical University, Shanghai 200032, China. mhjiang@shmu.edu.cn
Chen
D F
DF
He
X J
XJ
Yang
S
S
Zheng
P
P
Jiang
M H
MH
D000818:Animals; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D020746:Calcium Channels, L-Type / Q000187:drug effects*; D002469:Cell Separation; D006168:Guinea Pigs; D006352:Heart Ventricles; D017705:Lignans / Q000494:pharmacology*; D009206:Myocardium / Q000166:cytology*; D011083:Polycyclic Compounds / Q000494:pharmacology*
D002121:Calcium Channel Blockers; D020746:Calcium Channels, L-Type; D017705:Lignans; D011083:Polycyclic Compounds; C000604077:heteroclitin D; C082091:gomisin J