泮库溴铵对大鼠颈上交感神经元全细胞N型钙通道电流的影响及其机制的探讨

Effects of Pancuronium on Whole-cell N-type Calcium Currents of Rat Superior Cervical Ganglia

目的 研究泮库溴铵对大鼠颈上交感神经元细胞N型钙通道电流的影响。方法 酶 -机械法急性分离大鼠颈上交感神经元 (SCG)细胞。采用全细胞膜片钳技术 ,记录N型钙通道电流。通过自制“Y”型加药系统将以标准细胞外液稀释的泮库溴铵灌流至细胞周围。记录灌流前、灌流 30s后和冲洗 30s后的N型钙电流。在细胞内液内加入非水解性G蛋白抑制剂GDP·βS ,然后再以 10 μmol/L泮库溴铵灌流后观察N型钙电流的变化。结果 1、4、10、4 0 μmol/L的泮库溴铵可以使钙电流分别增强 12 .6 %、2 4 .2 %、5 6 .6 %和 2 1.9% ,而 10 0和4 0 0 μmol/L的泮库溴铵则分别使N型钙电流减少 14 .1%和 2 5 .5 %。在电极内液中加入G蛋白的非水解性竞争性拮抗剂GDP·βS后 ,10 μmol/L的泮库溴铵对N型钙电流的增强作用消失。 结论 较低浓度的泮库溴铵通过抑制G蛋白调控机制增强交感神经元N型钙通道电流 。

Purpose: To investigate the effects of pancuronium on N-type calcium currents of superior cervical ganglia (SCG) neurons. Methods: Single SCG neurons were acutely isolated using an enzymatic-mechanic method. The classic whole-cell patch-clamp technique was used to record the N-type calcium currents. Different concentrations of pancuronium diluted by standard external solution was added nearby the neurons through a 'Y' type tube system. The N-type calcium currents were recorded before and 30 seconds after pancuronium perfusion and also after washing out. Nonhydrolytic G-protein inhibitor GDP&middotβS 2 mmol/L were added to the internal solution to investigate the role of G-protein in the modulation of N-type calcium currents. Results: Pancuronium of 1, 4, 10, 40 μmol/L potentiated N-type currents(12.6%, 24.2%, 56.6% and 21.9%, respectively). Higher concentration of pancuronium (100 μmol/L and 400 μmol/L) inhibited the currents, with inhibiting rate 14.1% and 22.5%, respectively. While GDP&middotβS was added to the internal solution, pancuronium 10 μmol/L had no significant effects on calcium currents. Conclusions: Lower concentration pancuronium potentiates the N-type calcium currents of SCG neurons by inhibit the G-protein mechanism. That may at least partially explain the stimulatory effect of pancuronium on sympathetic nerve system.