TETRANDRINE EFFECTS ON CALCIUM CURRENTS IN CULTURED NEURONS OF FETAL MICE

TETRANDRINE, a bis-benzyl-isoquinoline alkaloid from the roots of Stef ania Tetranda blocks calcium currents in cultured neurones of the spin al cord of foetal mice. The concentration of half-maximal effect (Kd) measured 100 ms after the beginning of a depolarizing pulse (-80 mV - 0 mV) is 8 muM. While high- and low-voltage activated (HVA, LVA) curre nts are both blocked by Tetrandrine, the slowly inactivating HVA curre nts appear to be a primary target.