缺血对小鼠大脑皮层γ-氨基丁酸能神经元电生理特性的影响

Influence of ischemia on electrophysiology properties of cortical GABAergic neurons in mice

目的:探讨脑缺血诱导小鼠大脑皮层γ-氨基丁酸(GABA)能神经元电生理特性的变化。方法:取生后15～17d的FVB-Tg(GADGFP)4570Swn/J小鼠大脑做冠状切片(400μm),采用IR-DIC显微镜选择大脑皮层GA-BA能神经元,运用Axoclamp-2B放大器全细胞记录模式记录大脑皮层GABA能神经元动作电位的阈电位(Vts)和绝对不应期(ARP),分析群集发放的动作电位间距(ISI)和动作电位峰时程标准差(SDST)。结果:与缺血前相比,缺血后大脑皮层GABA能神经元产生群集动作电位的ISI和SDST降低(P<0.01),Vts和ARP延长(P<0.01)。结论:缺血改变导致GABA能神经元动作电位的不应期和阈电位升高,使大脑皮层GABA能神经元兴奋性降低,动作电位的编码能力降低。

Aim ： To study the changes of the electrophysiological properties of cortical Gamma aminobutyric acidergic （GABAergic） neurons induced by ischemia. Methods：The tissue blocks of cerebral cortex of GFP mice aged 15 - 17 d were quickly isolated, and the cortical slices （400 μm） were cut. Cortical GABAergic neurons labeled with GFP were selected under IR-DIC/fluorescent microscope. The threshold potentials （Vts） for firing spikes and absolute refractory periods （ARP） subsequent to each spike were recorded in whole-cell model using an Axoclamp-2B amplifier; and electrical signals were inputed into pClamp 9.2 for data acquisition and analysis of inter-spike interval（ISI） and standard deviation of spike timing（SDST）. Results： Compared with those before ischemia, ARP and Vts prolonged （P 〈 0. 01 ）, and ISI and SDST decreased（P 〈0.01 ）. Conclusion： The ischemia promotes ARP and Vts of sequential spikes and reduces the excitation and deteriorates spike encoding of GABAergie neuron.