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目的:研究E-4031对Na~+/Ca~(2+)交换电流的影响及其信号转导机制。方法:应用全细胞电压箝技术的斜坡脉冲程序,测定离体大鼠心肌细胞准稳态电流-电压关系曲线。结果:E-4031 5,10和20umol·L~(-1)分别使膜电位+50mV时的Ni~(2+)敏感电流从对照组(0.48±0.12)增加到(0.78±0.20),(96±0.16)和(1.15±0.13)pA/pF,蛋白激酶C激动剂-TPA 50nmol·L~(-1)使该电流从(0.60±0.16)增加到(1.33±0.25)pA/pF。蛋白激酶C拮抗剂Tamoxifen可完全阻断E-4031和TPA对该电流的刺激作用。结论:E-4031通过蛋白激酶C途径激动Na~+/Ca~(2+)交换系统。
Objective: To study the effect of E-4031 on Na ~ + / Ca ~ (2+) exchange current and its signal transduction mechanism. Methods: The whole-cell voltage-clamp technique was used to measure the quasi-steady-state current-voltage curve of isolated rat cardiomyocytes. Results: Sensitivity of Ni 2+ at membrane potential 50 mV was increased from 0.48 ± 0.12 to 0.78 ± 0.20 in E-4031, 5, 10 and 20 μmol·L -1, respectively 96 ± 0.16) and (1.15 ± 0.13) pA / pF, and the protein kinase C agonist-TPA 50 nmol·L -1 increased the current from (0.60 ± 0.16) to (1.33 ± 0.25) pA / pF. Tamoxifen, a protein kinase C antagonist, completely blocked E-4031 and TPA stimulation of this current. Conclusion: E-4031 activates Na ~ + / Ca ~ (2+) exchange system through protein kinase C pathway.