膜电位的不同波动对小鼠大脑皮质GABA能神经元内在特性的影响

刘秀平; 张茜; 王其一

doi:10.13898/j.cnki.issn.1000-2200.2019.12.002

膜电位的不同波动对小鼠大脑皮质GABA能神经元内在特性的影响

Effect of different fluctuations of membrane potential on the intrinsic characteristics of GABA neurons in mouse cerebral cortex

摘要

摘要:
目的探讨膜电位的不同波动对小鼠大脑皮质γ-氨基丁酸（GABA）能神经元内在特性影响及对神经编码的调控。
方法取出生15~20 d FVB-Tg（Gad GFP）45 704 Swn/J小鼠进行麻醉，断头取脑制作切片，将脑片置于充分氧合的人工脑脊液中继续孵育2 h。采用全细胞记录方法进一步探讨快速后超极化（fAHP）、慢速后超极化（sAHP）、动作电位不同复极和快速后去极化（fADP）对神经元内在特性的影响及对神经编码的调控。
结果fAHP和sAHP相比，fAHP影响下的动作电位的绝对不应期（ARP₂）较短（P < 0.01），阈值（Vts-Vr₃）较高（P < 0.01）；与fAHP相比，动作电位未完全复极时，ARP₂较短，当为阈强度0.25倍时，ARP₂最短（P < 0.05）；与fAHP比较，fADP程度越低，ARP₂越短，当在静息电位水平时，ARP₂最短（P < 0.05）。
结论大脑皮层GABA能神经元在整合突触输入后，当膜电位波动时其内在特性发生可塑性变化，不同输入模式通过影响大脑皮层GABA能神经元动作电位的内在特性，从而调控GABA能神经元对输入信号的编程能力。

Abstract:
ObjectiveTo explore the effects of different fluctuations of membrane potential on the intrinsic characteristics and regulation of neural coding of GABA-ergic neurons in mouse cerebral cortex.
MethodsThe brain slices were prepared from FVB-Tg(Gad GFP) 4570Swn/J mice(postnatal day 15-20), and incubated in artificial cerebrospinal fluid with sufficient oxygenation for 2 h.The effects of fast post-polarization(fAHP), slow post-hyperpolarization(sAHP), different repolarization of action potential and fast post-polarization(fADP) on the intrinsic characteristics of neurons and regulation of neural coding were further studied by whole-cell recording.
ResultsCompared with sAHP, the absolute refractory period(ARP₂) and threshold(vts-Vr₃) of the action potential under the influence of fAHP were shorter and higher, respectively(P < 0.01).Compared with fAHP, the ARP₂ was shorter when the action potential was not fully repolarized, and the ARP₂ was the shortest when the threshold intensity was 0.25 times(P < 0.05).Compared with fAHP, the lower the fADP level was, the shorter the ARP₂ was, and the ARP₂ was the shortest at the resting potential level(P < 0.05).
ConclusionsAfter the integrating synaptic input, the plasticity of intrinsic characteristics of cerebral cortex GABA-ergic neurons changes when the membrane potential fluctuates.Different input modes affect the intrinsic characteristics of action potential of cerebral cortex GABA-ergic neurons, thereby regulating the programming ability of GABA-ergic neurons to input signals.

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