EFFECT OF BERBERINE ON INTRACELLULAR FREE CA²⁺ CONCENTRATION IN CULTURED BRAIN CELLS

Intracellular free calcium concentration (Ca²⁺ i) was measured with Ca²⁺ 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 Ca²⁺ 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 μmol·L^-1 dose dependently inhibited norepinephrine and H₂O₂ induced Ca²⁺ i elevation. Ber at high concentration(10～100 μmol·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.