南方医科大学学报 ›› 2018, Vol. 38 ›› Issue (09): 1045-.doi: 10.12122/j.issn.1673-4254.2018.09.04

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β2-nAChR促进小鼠海马CA1和CA3锥体神经元GABAA受体的功能成熟

郑超,黄艳,张环环,查盈盈,汪萌芽   

  • 出版日期:2018-09-20 发布日期:2018-09-20

β2-nicotinic acetylcholine receptor promotes development of GABAA receptors in mouse hippocampal CA1 and CA3 pyramidal neurons

  • Online:2018-09-20 Published:2018-09-20

摘要: 目的探讨β2-烟碱型乙酰胆碱受体(β2-nAChR)在海马CA1和CA3锥体神经元的A型γ-氨基丁酸受体(GABAA-R)发育中 的作用。方法应用β2-nAChR基因敲除小鼠(β2-KO组)制备急性分离的海马CA1和CA3锥体神经元,应用穿孔膜片钳记录技 术记录GABAA-R选择性激动剂蝇蕈醇在CA1和CA3锥体神经元诱导的GABA电流,测试其平衡电位(EMus)和动力学指标,并 与野生型小鼠(WT组)进行比较。结果β2-KO组小鼠(n=4)CA1锥体神经元(n=7)的EMus为-31.7±3.5 mV,与WT组相比向去极 化偏移(P<0.05);CA3锥体神经元(n=4)的EMus为-16.1±4.6 mV,同样较WT组偏向去极化方向(P<0.01);与WT组小鼠不同,β2- KO组小鼠CA3和CA1神经元的EMus差异有统计学意义(P<0.05)。β2-KO组小鼠CA1和CA3神经元上都显示GABAA-R的失 敏显著减慢,衰减时间分别为2.2±0.2 s、3.2±0.1 s(WT组为1.6±0.1 s、2.3±0.1 s,P<0.05或P<0.01)。结论含β2的nAChR可能参 与促进小鼠海马CA1和CA3锥体细胞中GABAA-R的功能成熟。

Abstract: Objective To explore the role of β2-nicotinic acetylcholine receptor (β2-nAChR) in the development of γ- aminobutyric acid A type receptors (GABAA-Rs) in hippocampal CA1 and CA3 pyramidal neurons of mice. Methods The hippocampal CA1 and CA3 pyramidal neurons were acutely isolated from β2-nAChR gene knockout (β2-KO group) mice. GABA currents in CA1 and CA3 pyramidal neurons were induced with the selective GABAA-R agonist muscimol and recorded using perforated patch-clamp recording technique. The GABA currents of CA1 and CA3 pyramidal neurons were tested for their equilibrium potentials (EMuss) and kinetic parameters and were compared with the measurements in wild-type mice (WT group). Results The mean EMus of CA1 neurons (n=7) of β2-KO mice (n=4) was -31.7±3.5 mV, showing an obvious depolarizing shift compared with the WT mice (P<0.05); the mean EMus of CA3 neurons (n=4) was -16.1±4.6 mV, also showing a depolarizing shift (P<0.01). The difference in the EMuss between CA3 and CA1 neurons in β2-KO mice, but not in WT mice, was significant (P< 0.05). The GABAA-R desensitization was significantly slowed down in both CA1 and CA3 neurons of β2-KO mice, with decay time of 2.2±0.2 s and 3.2±0.1 s, respectively, significantly longer than those in WT mice (1.6±0.1 s and 2.3±0.1 s, respectively; P< 0.05). Conclusion β2-containing nAChRs may promote the functional maturation of GABAA-R in CA1 and CA3 pyramidal cells in mouse hippocampus.