小檗胺对高钾,去甲肾上腺素及咖啡因引起大鼠心肌细胞内钙动拮？…

Antagonistic effects of berbamine on [Ca2+]i mobilization by KCl, norepinephrine, and caffeine in newborn rat cardiomyocytes.

AIM: To study the effects of berbamine (Ber) on intracellular calcium concentration (Ca2+]i) mobilized by KCl depolarization, norepinephrine (NE), and caffeine. METHODS: Ca2+]i was measured with fluorescent intensity (FI) by confocal microscope in single cultured cardiomyocytes of newborn rats loaded with Fluo 3-AM 2 mumol.L-1. RESULTS: FI value of Ca2+]i in control level was 248 +/- 70 in the presence of extracellular calcium 1.5 mmol.L-1 and was not changed by Ber 3-30 mumol.L-1. KCl (60 mmol.L-1)- and NE (30 mumol.L-1)-induced Ca2+]i mobilizations were inhibited (P < 0.01) by Ber 30 mumol.L-1, similar to that of verapamil (Ver). The inhibitory effect of Ber on Ca2+]i induced by KCl was further increased (P < 0.05) in the presence of egtazic acid 3 mmol.L-1, but that on Ca2+]i induced by NE was not changed. The Ca2+]i mobilized by caffeine 80 and 160 mumol.L-1 in D-Hanks' solution was not affected (P > 0.05) by Ber and Ver. CONCLUSION: Ber possessed the antagonistic effects on Ca2+]i increases via voltage-dependent Ca2+ channel and receptor-operated Ca2+ channel in newborn rat cardiomyocytes, but without effect on intracellular Ca2+ release.