盐酸埃他卡林对脑神经元钠、钾、钙通道的影响

目的　研究盐酸埃他卡林 (Ipt)对脑神经元钠、钾、钙通道的影响。方法　在原代培养的大鼠海马神经元上 ,应用膜片钳全细胞记录技术观察Ipt对钠、钾、钙离子通道电流的影响。结果　Ipt对钠、钙电流幅度以及电流 -电压曲线无影响 ,可增强外向钾电流幅度 ,使电流 -电压曲线上移。其中 ,Ipt 1、10、10 0 μmol·L-1分别使钾通道电流峰值增大为给药前的 (12 1 9± 8 1) %、(114 7± 7 1) %和 (10 9 1±10 0 ) % (P <0 0 1～ 0 0 5 )。给予盐酸埃他卡林 1μmol·L-1的同时给予ATP敏感性钾通道拮抗剂格列本脲 30 μmol·L-1时 ,对钾通道电流无影响。结论　盐酸埃他卡林对脑神经元ATP敏感性钾通道具有激活作用 ,它不影响神经元钠通道和钙通道

Effects of iptakalim hydrochloride on cerebral neuronal sodium,calcium and potassium channels

AIM To investigate the effects of iptakalim hydrochloride (Ipt) on cerebral neuronal sodium, calcium and potassium channels. METHODS The effects of Ipt on sodium, calcium and potassium channels in cultured hippocampal neurons was observed using whole-cell recording technique. RESULTS Ipt had no significant effect on Na +, Ca 2+ currents, but significantly increased the outward K + currents. This enhancement of Ipt was inhibited by synchronously application of glibenclamide. Upon the administration of Ipt 1, 10, 100 μmol·L -1, the outward K + current was significantly increased to (121.9±8.1)%, (114.7±7.1)%, (109.1±10.0)% respectively (n=6～9, P<0.01～0.05). This enhancement of Ipt was inhibited by synchronously application of glibenclamide 30 μmol·L -1, a relatively specific inhibitor of ATP-sensitive K + channels. CONCLUSIONS Iptakalim hydrochloride, with no significant effects on sodium and calcium channels, could activate ATP-sensitive potassium channels selectively.