Effects of (1R,9S)-β-Hydrastine on Intracellular Calcium Concentration in PC12 Cells

Abstract

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