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员的拮抗作用(英文)

Antagonistic effects of berbamine on [ Ca^(2 +) ] _i mobilization by KCl, norepinephrine, and caffeine in newborn rat cardiomyocytes

目的:研究小檗胺(Ber)对氯化钾、NE及咖啡因引起大鼠培养心肌细胞[Ca^(2+)]_i动员的影响,方法:Fluo 3-AM负载后,共聚焦法测定心肌细胞[Ca^(2+)]_i荧光强度的变化。结果:Ber对心肌细胞静息[Ca^(2+)]_i水平无影响,但可剂量依赖性地抑制KCl60mmol·L^(-1)及NE 30 μmol·L^(-1)引起的内钙动员(P<0.01),此作用与维拉帕米相似.Egtazic acid3 mmol·L^(-1)并不能增强Ber对NE引起的[Ca^(2+)]_i升高的抑制作用,无外钙时,咖啡因80-160μmol·L^(-1)的[Ca^(2+)]_i动员不受Ber的影响(P>0.05),结论:Ber与维拉帕米相似,对大鼠心肌细胞靠电压依赖性和受体操纵性钙通道而升高的胞[Ca^(2+)]_i有拮抗作用,并不影响[Ca^(2+)]_i释放。

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 μmol· L-1. RESULTS: Fl 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 μmol·L-1. KCl (60 mmol· L-1)- and NE (30 μmol· L-1)-induced [Ca2+]i mobilizations were inhibited (P < 0.01) by Ber 30 μmol·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 μmol·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.