ROLES OF CGMP-GATED CHANNELS IN RETINAL BIPOLAR NEURONS

描述(申请者描述)：本项目的目标是 了解视网膜神经递质反应的分子机制 双极神经元，重点是环核苷酸门控(CNG)的作用 频道。来自光感受器的视觉信号被输送到其余的 大脑完全通过双极神经元，因此占据了中枢 在视网膜信息处理中的位置。视觉的分离 信息进入ON通路(在该通路中，细胞对 光)和OFF途径(细胞对光作出反应的超极化) 发生在双极神经元中，位于视觉系统的第一个突触。这个 拟议的研究项目将探索产生 光感受器细胞与双极细胞突触上的ON通路 神经元。在这个突触，谷氨酸从光感受器释放出来 通过激活转导级联使双极细胞超极化 最终导致阳离子通道关闭。这些阳离子通道可以是成员 CNG通道家族中的一员，当环状GMP直接与 通道的细胞内部分。电子记录和电子记录的组合 将使用荧光成像技术来确定CNG的作用 双极细胞谷氨酸反应中的通道和环GMP。其他 CNG通道的潜在作用也将被探索，例如调制 双极细胞突触终末的神经递质释放。 分子生物学技术将被用来鉴定和表征 CNG通道亚型在双极神经元中表达。从氨基酸序列 来源于编码CNG通道亚型的互补DNA，选择性 将产生可用于定位通道亚型的抗体 在分离的细胞和视网膜组织中。CNG的生物物理特性 在双相神经元中发现的通道亚型将在双相神经元中进行 神经元和转导编码a基因全长互补DNA的细胞 特定通道子类型。拟议中的实验将提供新的信息 关于一类重要的视网膜神经元和意志的突触反应 为特定类型的CNG通道指定生理角色 这些神经元。因为环核苷酸门控通道存在于各种 整个神经系统的细胞类型，建议的结果 该项目还将对 大脑的其他部分。

DESCRIPTION (Applicant's Description): The goal of this project is to understand the molecular mechanisms of neurotransmitter responses in retinal bipolar neurons, with a focus on the roles of cyclic nucleotide-gated (CNG) channels. Visual signals from the photoreceptors are funneled to the rest of the brain exclusively through bipolar neurons, which therefore occupy a central position in retinal information processing. The separation of visual information into the ON pathway (in which cells depolarize in response to light) and the OFF pathway (in which cells hyperpolarize in response to light) occurs in bipolar neurons, at the first synapse in the visual system. The proposed research project will explore the cellular mechanisms that generate the ON pathway at the synapse between photoreceptor cells and ON bipolar neurons. At this synapse, glutamate released from the photoreceptor hyperpolarizes ON bipolar cells by activating a transduction cascade culminating in closure of cation channels. These cation channels may be members of the family of CNG channels, which open when cyclic GMP binds directly to the intracellular portion of the channel. A combination of electrical recording and fluorescence imaging techniques will be used to establish the role of CNG channels and cyclic GMP in the glutamate response of ON bipolar cells. Other potential roles of CNG channels will also be explored, such as modulation of neurotransmitter release in the synaptic terminal of the bipolar cell. Molecular biological techniques will be used to identify and characterize the CNG channel subtypes expressed in bipolar neurons. From amino acid sequences derived from complementary DNA encoding CNG channel subtypes, selective antibodies will be produced that can be used to localize the channel subtypes in isolated cells and retinal tissue. Biophysical characterization of CNG channel subtypes found in bipolar neurons will be carried out both in bipolar neurons and in cells transfected with full-length complementary DNA encoding a specific channel subtype. The proposed experiments will provide new information about the synaptic responses of an important class of retinal neurons and will specify physiological roles for specific types of CNG channels expressed in these neurons. Because cyclic nucleotide-gated channels are found in a variety of cell types throughout the nervous system, the results of the proposed project will also have general implications for cellular communication in the other parts of the brain.