多巴胺增强培养新生大鼠DRG神经元ATP激活电流

目的 :探讨多巴胺对ATP激活电流的调制作用。方法 :实验在培养的新生大鼠脊髓背根神经节细胞上进行 ,应用全细胞膜片钳技术记录出ATP和多巴胺激活的电流。结果 :在被检的DRG细胞中 ,有 6 2 % (39/ 6 3)的神经元对ATP和多巴胺都敏感。在预加 10 -8,10 -7,10 -6和 10 -5mol/L多巴胺后 ,ATP的激活电流分别增加到 139.7% ,141.5 % ,149.9% ,149.1% ;呈剂量依赖性。用D1的拮抗剂SCH - 2 3390能取消此增强作用 ;在电极中灌注H - 7(PKC ,PKA抑制剂 )也能取消此增强作用。结论 :多巴胺对ATP激活电流的增强作用是多巴胺作用于D1受体 ,通过胞内第二信使 ,使P2X受体通道复合体胞内磷酸化所致。

Dopamine Potentialization of ATP-Activated Currents in Cultured DRG neurons

Objective To explore whether or not dopamine modulates the response mediated by P2X receptor. Methods Experiments were carried out on the DRG neurons of cultured newborn rats. ATP- and dopamine-activated currents were recorded using the whole cell patch clamp technique. Results 62% of the measured neurons (39/63) were sensitive to both of ATP and dopamine. When the neurons were treated with dopamine prior to the application of ATP, the ATP-activated current was potentiated. The effect of dopamine was dose-dependent.With dopamine concentration of 10 -8 ,10 -7 ,10 -6 and 10 -5 mol/L, the ATP-activated current was potentiated by 139.7%, 141.5%, 149.9%, 149.1%. The potentiation can be blocked by SCH-23390 (D 1 receptor antagonist). The intracellular application of H7(a potent inhibitor of PKC and PKA) could abolish the potentiation of dopamine on ATP-activated current. Conclusion The dopamine potentiaton of the ATP-activated current might be the result of intracellular phosphorylation of P2X receptor.