小鼠中脑下丘神经元对单、双耳听觉信息突触反应的多样性研究

Diversity of Synaptic Responses of Inferior Colliculus Neurons to Monaural and Binaural Auditory Stimulations in Mice

林涛;何娜;刘秀萍;鄢俊;

1:广州市第一人民医院麻醉科

2:加拿大卡尔加里大学Cumming医学院Hotchkiss脑科研究所生理学与药理学系

3:广州医科大学附属第二医院神经内科

摘要
目的研究小鼠中脑下丘单个神经元对单耳对侧、同侧声刺激的突触反应及双侧同时刺激的整合反应,探索其潜在的神经生理学基础与神经环路。方法 52只正常C57小鼠,采用声刺激系统记录下丘单个神经元对单耳对侧、单耳同侧声刺激的频率-幅度反应域(frequency-amplitude response areas,FARA),获得神经元的特征频率(characteristic frequency,CF)和最低阈值(minimum threshold, MT)。采用活体全细胞膜片钳技术,在最适声刺激条件下(即声音参数为CF与MT),记录下丘同一个神经元分别对单耳对侧、单耳同侧声刺激的突触反应,以及双侧声音同时刺激时的突触整合反应,对记录到的突触反应及整合反应进行分类分析。结果共记录到146个下丘神经元,CF-对侧与CF-同侧分别为14.9±4.8、14.7±5.0 kHz,两者成直线相关且相关系数为1.025 8;MT-对侧为19.3±19.3 dB,显著低于MT-同侧(45.1±18.6 dB),差异有统计学意义(P<0.001)。根据神经元对单耳刺激的反应是兴奋(excitation, E)、无反应(no response, O)还是抑制(inhibition, I),可将这146个神经元分成7种不同类型,即EE、EO、EI、II、IO、IE和CM(complex-mode,CM)双耳神经元,分别占66.4%(97/146)、15.8%(23/146)、4.1%(6/146)、6.8%(10/146)、1.4%(2/146)、1.4%(2/146)和4.1%(6/146)。根据双耳整合特性,EE神经元可分成抑制EE/I、易化EE/F和无整合EE/N三种类型,分别占38.1%(37/97)、20.6%(20/97)和41.2%(40/97)。EO和II神经元对双耳信息的整合反应可出现抑制和无整合两种,EI神经元仅表现出抑制的整合反应,而IO和IE神经元则呈双耳无整合效应。结论 EE、EO、EI、II、IO、IE和CM这7种不同类型的下丘双耳神经元各自具有不同的双侧突触结构和神经环路。
关键词
下丘;兴奋性突触后电位;抑制性突触后电位;双耳整合
基金项目(Foundation):
作者
林涛;何娜;刘秀萍;鄢俊;
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