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Study of synaptic transmissions on hair cells

毛细胞突触传递的研究

基本信息

批准号：
01440021
负责人：
OHMORI Harunori
金额：
$ 17.54万
依托单位：
KYOTO UNIVERSITY (1992)Okazaki National Research Institutes (1989-1991)
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (A)
财政年份：
1989
资助国家：
日本
起止时间：
1989 至 1992
项目状态：
已结题

项目摘要

Hair cells of the inner ear is the transducer cell of mechanical energy. Namely, the informations of sound, balance and accelerations are transduced into the electrical signal and then transmitted to the central nervous system. From the central nervous system some feedback informations are returned to the peripheral hearing organ to inhibit the hair cell. I have aimed in this research to investigate both the afferent and efferent synapses on to the hair cell, by utilizing a slice preparation of the cochlear. However, making a good slice of the hearing organ was extremely difficult, because of the mixture of hard and soft structures. I have therefore focused on the analysis by utilizing cutout preparation of vestibular organ and on the experiments with isolated hair cells. Afferent synapse activities were recorded in the cut-out preparation of vestibular organ, and the differences of the synaptic potential appearance, probably the mechanism of synapse transmission too, were detected between bouton type and calyx type synapses. The isolated hair cells were mainly studied in the analysis of acetylcholine effects. Acetylcholine hyperpolarized the hair cell membrane by increasing intracellular Ca concentration and by activating K conductance. The transmitter released from hair cell was concluded most likely as glutamate also by utilizing the isolated hair cell preparation together with cultured neuron with high glutamate receptor sensityvity.

内耳毛细胞是机械能的传导细胞。也就是说，声音、平衡和加速度的信息被转换成电信号，然后传输到中枢神经系统。来自中枢神经系统的一些反馈信息被返回到外周听觉器官以抑制毛细胞。在这项研究中，我的目的是通过利用耳蜗的切片制备来研究毛细胞上的传入和传出突触。然而，由于硬和软结构的混合，制作一个好的听觉器官切片是极其困难的。因此，我将重点放在利用前庭器官切割制备的分析和分离毛细胞的实验上。在前庭器官切割准备过程中记录了传入突触的活动，并检测了钮扣型和花萼型突触突触电位外观的差异，以及突触传递的机制。对离体毛细胞进行了乙酰胆碱效应分析。乙酰胆碱通过增加细胞内钙离子浓度和激活钾电导使毛细胞膜超极化。利用分离的毛细胞制剂和培养的谷氨酸受体敏感性高的神经元，推测毛细胞释放的递质最有可能是谷氨酸。