铝对大鼠背根神经节分离神经元GABA激活电流的调制作用

目的　研究三氯化铝 (AlCl3)对大鼠背根神经节分离神经元γ 氨基丁酸 (GABA)激活电流的作用。方法　应用全细胞膜片钳技术在新鲜分离的大鼠背根神经节 (DRG)神经元上观察AlCl3 对GABA激活电流的影响。结果　大部分受检细胞 (4 6 /5 8)对GABA(1～ 10 0 0 μmol·L-1)敏感。在这 46个细胞中 ,单独加AlCl3 可引起三类膜反应 :(1)外向电流 (3/4 6 ) ;(2 )内向电流 (5 /4 6 ) ;(3)无反应 (38/4 6 )。与GABA激活的内向电流相比 ,AlCl3 激活电流幅值要小得多。预加较低浓度 (≤ 10 0 μmol·L-1)AlCl3 对GABA激活电流影响如下 :产生增强效应的细胞为 32 /38,并具有浓度依赖性 ;产生抑制作用的细胞为 4/38;无明显作用的细胞为 2 /38。较高浓度 (10 0 0 μmol·L-1)AlCl3 抑制GABA激活电流 (n2 0 0 0 0 3 16收稿 ,2 0 0 0 0 7 12修回1 江西医学院生理教研室 ,南昌　 330 0 0 6作者简介 :梁尚栋 ,男 ,41岁 ,医学硕士 ,副教授 ,主要研究方向 :神经生理学 ;李之望 ,男 ,教授 ,主要研究方向 :神经生理和药理学=8)。AlCl3 对GABA激活电流的增强作用既可增强峰电流也可增强稳态部分。结论　AlCl3 改变GABAA 受体的机能。

Modulation of AlCl_3 on GABA-activated currents in isolated rat DRG neurons

AIM To study the modulation of AlCl 3 on GABA activated currents in isolated rat dorsal root ganglion (DRG) neurons. METHODS Using whole cell patch clamp technique to investigate the effects of AlCl 3 on GABA activated currents in isolated rat DRG neurons. RESULTS The majority of the neurons examined(46/58) were sensitive to GABA in the concentration range from 1 to 1 000 μmol·L -1 . In the 46 GABA sensitive cells, responses induced by AlCl 3 manifested three types: (1) outward current(3/46); (2) inward current(5/46) and (3) no detectable response(38/46). As compared with GABA activated current, the amplitude of AlCl 3 activated current was smaller. Preapplication with low concentrations of AlCl 3 (≤100 μmol·L -1 ), the GABA activated current in majority of the cells(32/38) was potentiated, which was dose dependent, the current in a few cells(4/38) was inhibited, while the remaining two(2/38) showed no effect. At higher concentration( 1 000 μmol·L -1 ), AlCl 3 inhibited the GABA activated current( n =8). It was found that AlCl 3 potentiated both the peak value of and the steady state value of GABA activated currents. CONCLUSION AlCl 3 can modulate the function of GABA A receptors.