[Effect of berberine on intracellular free CA2+ concentration in cultured brain cells]

Intracellular free calcium concentration ([Ca2+]i) was measured with Ca(2+)-sensitive fluorescent indicator, Fura-2/AM, in cultured brain cells using AR-CM-MIC cation measurement system, and the effects of berberine (Ber) on the changes in [Ca2+]i induced by CaCl2, norepinephrine, KCl and H2O2 were studied. The results indicate that the resting [Ca2+]i was 35 +/- 8 nmol.L-1 in Ca(2+)-free Hank's solution. Ber showed no effect on the resting [Ca2+]i when the extracellular Ca2+ were 0.01-10 mmol.L-1. Ber 1-100 mumol.L-1 dose-dependently inhibited norepinephrine and H2O2 induced [Ca2+]i elevation. Ber at high concentration (10-100 mumol.L-1) inhibited K(+)-induced [Ca2+]i elevation. This suggests that the inhibitory effects of Ber on norepinephrine, K(+)-, and H2O2-induced [Ca2+]i elevation may be one of the mechanisms against cerebral ischemia.