小檗碱对培养大鼠心肌细胞胞内游离Ca2+的作用

利用Fura-2技术和AR-CM-MIC阳离子测定系统,直接观察了小檗碱对培养大鼠心肌细胞胞内Ca²⁺]i的影响。结果显示:小檗碱可明显升高心肌细胞静息Ca²⁺]i且具饱合性,维拉帕米和CoCl₂对其有一定的抑制作用;小檗碱与高K⁺,高Ca²⁺,去甲肾上腺素,哇巴因合用比单用上述激动剂更能明显增高Ca²⁺]i;维拉帕米对其有抑制作用;在胞外无外Ca²⁺和无外Ca²⁺,外K⁺,外Na⁺时,小檗碱30～200μmol·L^-1仍能升高静息Ca²⁺]i,维拉帕米只对前者有一定抑制作用。结果提示:小檗碱可能通过促胞外Ca²⁺内流和胞内Ca²⁺释放等途径有限度地增高心肌细胞内游离Ca²⁺浓度,显示强心作用。

EFFECT OF BERBERINE ON CYTOSOLIC FREE CALCIUM OF RAT MYOCARDIAL CELLS IN VITRO

In order to verify the inotropic effect of berberine (Ber) on myocardial tissues, the effect of Ber on cytosolic free calcium Ca2+]i in cultured rat single myocardial cells were examined by using Fura-2/AM and AR-CM-MIC cation measurement system. Ber (10-400 mumol.L-1) was found to increase the resting Ca2+]i and saturate at about 200 mumol.L-1. The Ca2+]i increase was not depressed by atropine, phentolamine, propranolol and tetrodotoxin, but was inhibited by verapamil (Ver) 3 mumol.L-1 or CoCl2 10 mmol.L-1. The Ca2+]i increase induced by Ber (30 mumol.L-1) added to stimulating agents as KCl, CaCl2, NE or Oua was stronger than that induced by stimulating agents only and Ver 3 mumol.L-1 still showed inhibitory effects on the Ca2+]i increase. Under Ca(2+)-free or Ca(2+)-, K+, Na(+)-free conditions, Ber (30-200 mumol.L-1) still showed ascending effects on Ca2+]i, and Ver 3 mumol.L-1 only inhibited the Ber effects in Ca(2+)-free condition. The results suggest that Ber might induce moderate Ca2+]i increase via Ca2+ influx and intracellular Ca2+ release, and show positive inotropic effect.