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Studies on the neural circuit and neurotransmitters in the mammalian retina.

研究哺乳动物视网膜中的神经回路和神经递质。

基本信息

批准号：
02454124
负责人：
KANEKO Akimichi
金额：
$ 4.35万
依托单位：
Keio University (1991)Okazaki National Research Institutes (1990)
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1990
资助国家：
日本
起止时间：
1990 至 1991
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-02454124/
关键词：
ganglion cell sodium current acetylcholine bipolar cell calcium current retina L-glutamate cat イオン電流 X細胞 W細胞

项目摘要

The vertebrate retina is a small central nervous system in which the visual information captured by photoreceptors are processed. All visual signals are encoded into the train of action potentials that travel through the optic nerve to higher visual centers. Despite that a vast amount of studies have been made on mammalian retina on the light-evoked responses of the optic nerve, studies on the underlying intraretinal mechanisms are quite limited in the mammalian retina. In stead, lower vertebrates have been used as model preparations, since mammals and the lower vertebrates have similar structures of the retina and the light-evoked responses of the optic nerve show similar characteristics.The aim of the present study was to elucidate ionic currents and transmitter actions on the isolated retinal cells dissociated from mammals. We achieved following studies and made findings listed below. (1)We established tlie method to dissociate mammalian retinal cells in good condition. (2)We established the method to identify solitary ganglion cells by retrograde labeling using Dil. (3)We found that X- and W-cells has a sodium. current with different inactivation kinetics : I_<Na> of X-cells recover rapidly froin inactivation, while recovery was slow in W-cells. (4)We found that cat retinal horizontal cells have qualitatively the same type of ionic currents as horizontal cells of the lower vertebrates. (5)We found two types of bipolar cells in the cat retina. Tlie one type responded to L-glutamate with an outward current response accompanied by a conductance decrease, while tlie other type responded with an inward current accompanied by a conductance increase. The former cells correspond to those showing depolarizing light responses, while the latter correspond to OFF bipolar cells showing hyperpolarizing light responses.

脊椎动物的视网膜是一个小的中枢神经系统，光感受器捕捉的视觉信息在其中进行处理。所有的视觉信号都被编码成一系列动作电位，通过视神经传递到更高的视觉中心。尽管已经对哺乳动物视网膜进行了大量关于视神经光诱发反应的研究，但对哺乳动物视网膜潜在的视网膜内机制的研究相当有限。取而代之的是，由于哺乳动物和低等脊椎动物的视网膜结构相似，视神经的光诱发反应也表现出相似的特征，低等脊椎动物被用作模型准备。本研究的目的是阐明从哺乳动物分离的视网膜细胞上的离子电流和递质作用。我们完成了以下研究，并取得了如下研究成果。(1)建立了分离哺乳动物视网膜细胞的方法。(2)建立了DIL逆行标记鉴定孤立神经节细胞的方法。(3)我们发现X-细胞和W-细胞含有钠。电流失活动力学不同：X细胞从失活状态恢复较快，而W细胞恢复较慢。(4)我们发现猫视网膜水平细胞与低等脊椎动物的水平细胞具有相同类型的离子电流。(5)在猫视网膜中发现两种类型的双极细胞。一种类型对L-谷氨酸的反应是外向电流伴随电导的降低，另一种类型的反应是内向电流伴随电导的增加。前者对应于那些表现出去偏振光响应的细胞，而后者对应于表现出超极化光响应的非双极细胞。