白屈菜赤碱对PC12细胞乙酰胆碱诱发电流的快速抑制作用

采用全细胞膜片钳技术研究蛋白激酶C(PKC)选择性抑制剂白屈菜赤碱(CHT)对PC12细胞上乙酰胆碱(30 μmol·L^-1)诱发电流(I_ACh)的影响. 研究表明CHT(0.1-10 μmol·L^-1)预温育细胞5 min可使I_ACh峰值受抑制，此作用呈浓度依赖性，可逆性和非电压依赖性. CHT(5 μmol·L^-1)温育细胞6 min内对I_ACh的抑制作用呈时间依赖性. 通过微电极将更为有效的PKC抑制剂PKCI 19-31(0.1-5 μmol·L^-1)透析入细胞内以阻断PKC，并不影响CHT抑制I_ACh的作用. 以上结果提示：CHT对PC12细胞I_ACh有快速抑制作用，此作用与抑制PKC无关，而可能是一种新的药理作用.

Rapid inhibitory effect of chelerythrine on acetylcholine-induced current in PC12 cells

The effect of chelerythrine(CHT), a selective protein kinase C(PKC) inhibitor, on acetylcholine induced current(I_ACh) in PC12 cells was investigated by whole- cell clamping technique. It was found that extracellular pretreating cells with CHT 0.1-10 μmol·L^-1 for 5 min induced a rapid inhibition on the peak of I_ACh. This effect was concentration-dependent, reversible and voltage-independent. The inhibition on I_ACh induced by pretreating cells with CHT(5 μmol·L^-1) in 6 min was time- dependent. Intracellular dialysis with the specific inhibitor of PKC, the pseudosubstrate PKC inhibitor PKCI 19-31 (0.1-5 μmol·L^-1), had no effect on the inhibition induced by CHT. These results suggest that CHT have rapid inhibitory effect on I_ACh in PC12 cells, which is independent of its effect on PKC and maybe mediated by a new pharmacological mechanism.