摘要：(1 R ,9 S )-β-Hydrastine (BHS) decreases the basal intracellular Ca2+ concentration ([Ca2+]i) in PC12 cells.5) This study examined the effects of (1 R ,9 S )-BHS on [Ca2+]i in PC12 cells. (1 R ,9 S )-BHS at 10—100 μ M in combination with a high extracellular K+ level (56 m M ) inhibited the release of dopamine in a concentration-dependent manner with an IC50 value of 66.5 μ M . BHS at 100 μ M inhibited the sustained increase in [Ca2+]i induced by a high K+ level (56 m M ), and had an inhibitory effect on the 2 μ M nifedipine-induced blockage of the K+-stimulated sustained increase in [Ca2+]i. In addition, (1 R ,9 S )-BHS at 100 μ M prevented the rapid and sustained increase in [Ca2+]i elicited by 20 m M caffeine, but did not have an effect on the increase induced by 1 μ M thapsigargin, in the presence of external Ca2+. These results suggest that the active sites of (1 R ,9 S )-BHS are mainly L-type Ca2+ channels and caffeine-sensitive Ca2+-permeable channels in PC12 cells.
