发育中小鼠大脑皮层GABA能神经元电生理特性的变化

Changes of electrophysiological characteristics of cortical GABAergic neurons during mouse development

目的探讨小鼠发育过程中,大脑皮层γ-氨基丁酸(GABA)能神经元电生理特性的变化。方法取出生后6～12 d(未睁眼组)、15～22 d(睁眼组)小鼠,制作脑片,25℃下人工脑脊液孵育1 h,使用全细胞记录方法记录GABA能神经元电生理特性:动作电位的绝对不应期(ARP)、群集发放的动作电位间距(ISI)和动作电位峰时程标准差(SDST)。运用Clampfit 10软件分析电流刺激强度改变对发育中小鼠大脑皮层GABA能神经元发育的电生理特性的影响。结果睁眼组较未睁眼组ARP缩短,ISI缩短,SDST减小;随刺激强度的增加,小鼠大脑皮层GABA能神经元ARP缩短,ISI缩短,SDST减小。结论发育过程中,由于小鼠大脑皮层GABA能神经元ARP缩短,调控动作电位发放的时程及精确性增强;刺激强度的增加有利于GABA能神经元的功能发育。

Objective To investigate changes of electrophysiological characteristics of cortical GABAergic neurons during mouse development. Methods Mice aged 6 -12 d （eye-unopen group） and 15 -22 d （eye- open group） were sacrificed. Cortical slices were quickly produced and immersed in oxygenated artificial cerebrospinal fluid at 25 ＊（3 for 1 h. The electrophysiological characteristics of GABAergic neurons were recorded by Axoclamp-2B amplifier, including absolute refractory period （ARP）, inter-spike interval （ISI）, standard deviation of spike timing （SDST） of action potential. The effects of changing depolarizing stimulus intensity on electrophysiological characteristics of cortical GABAergic neurons of developing mice were analyzed with Glampfit 10 software. Results ARP, ISI, and SDST in eye-open group reduced as compared with the eye-unopen group. ARP, ISI, and SDST of mouse cortical GABAergic neurons reduced with the increase in stimulus intensity. Conclusion Reduced ARP of mouse cortical GABAergic neurons during development results in improved regulation of timing and accuracy for faring action potential. The increase in stimulus intensity facilitates the functional development of GABAergic neurons.