omega-conotoxin-(conus-magus) and furnidipine

The effects of the synthetic analogue of the toxin from the venom of the funnel-web spider Agenelopsis aperta (sFTX) on whole-cell Ba2+ currents through Ca2+ channels were studied in cultured bovine chromaffin cells. sFTX selectively and reversibly blocked a significant component (55 +/- 3%) of the whole-cell IBa. Effects of sFTX were additive to those of omega-conotoxin GVIA, a selective blocker of N-type Ca2+ channels, and those of furnidipine, a novel dihydropyridine L-type Ca2+ channel blocker. We conclude that the cultured bovine chromaffin cells, in addition to N- and L-type Ca2+ channels, possess a P-type component in their whole-cell currents through their Ca2+ channels.

Topics: Adrenal Medulla; Animals; Barium; Calcium Channel Blockers; Calcium Channels; Cattle; Cells, Cultured; Dihydropyridines; Dose-Response Relationship, Drug; Ion Channel Gating; Kinetics; omega-Conotoxins; Peptides; Polyamines