HORIZONTAL CELL INFLUENCES UPON GANGLION CELL PROPERTIES

本研究项目是一项关于突触的实验研究， 脊椎动物视网膜的组织。 虽然接受者 神经节细胞的场特性与视觉 功能，很少有人知道关于突触前通路 这是这些细胞特性的基础。 本研究 建议将研究水平细胞对 兔视网膜神经节细胞感受野特性及 将研究这个水平细胞到神经节细胞 通路由光水平和突触输入调制， 兔子和鱼视网膜中的水平细胞。 水平细胞将被细胞内电流极化 同时从附近的单个单元记录进样 神经节细胞锋电位活动。 这些实验将决定 水平细胞是否有助于神经节细胞的感受性 字段属性及其周围，以及是否 水平细胞影响部分但不是全部神经节细胞 兔子视网膜的分类 因为不同种类的兔子 水平细胞接受不同比例的杆和锥 输入，这些细胞类型的极化，这将被确定为 将有助于揭示视杆细胞和视锥细胞通路 对神经节细胞感受野产生不同的影响 特性. 还将在治疗期间应用递质拮抗剂。 向水平单元注入电流，以确定 具有已知作用的药物可以改变电流的作用， 神经节细胞放电。 这些数据可以 阐明外层视网膜的电路。 关于《公约》的其他研究 鲤鱼和兔子将研究可能的调制 水平细胞感受野大小和反应性， 长时间黑暗对神经节细胞周围大小和敏感性的影响 适应，多巴胺和cAMP。 神经回路和发射器功能的知识， 哺乳动物视网膜将增加对人类视网膜的了解 过程，增强视网膜病变的诊断， 为视网膜疾病的药物治疗提供了基础。的 多巴胺能神经元的特异性影响 视网膜将进一步加深我们对视觉病理的理解 与帕金森氏症有关。

This research project is an experimental study of the synaptic organization of the vertebrate retina. Although the receptive field properties of ganglion cells are quite pertinent to visual function, little is known concerning the presynaptic pathways which underlie the properties of these cells. This research proposal will examine the influence of horizontal cells upon the receptive field properties of ganglion cells in the rabbit retina and will investigate whether this horizontal cell to ganglion cell pathway is modulated by light level and by synaptic input onto horizontal cells in the rabbit and fish retinas. Horizontal cells will be polarized by intracellular current injections while simultaneously recording from nearby single-unit ganglion cell spike activity. These experiments will determine whether horizontal cells contribute to ganglion cell receptive field properties in addition to their surrounds, and whether horizontal cells influence some, but not all, of the ganglion cell classes of the rabbit retina. Because different types of rabbit horizontal cells receive different proportions of rod and cone input, polarization of these cell types, which will be identified by dye injection, will help reveal whether rod and cone pathways exert different effects upon ganglion cell receptive field properties. Transmitter antagonists will also be applied during current injections into horizontal cells to determine whether drugs with known actions can alter the effects of current injection on ganglion cell discharges. These latter data may elucidate circuitry of the outer retina. Additional studies on the carp and rabbit will investigate the possible modulation of horizontal cell receptive field size and responsiveness and ganglion cell surround size and sensitivity by prolonged dark adaptation, dopamine and cyclic AMP. Knowledge of neural circuitry and transmitter function in mammalian retina will increase understanding of human retinal processes, enhance the diagnosis of retinal pathologies and provide the basis for drug therapy for retinal disorders. The identification of specific influences of dopaminergic neurons in the retina will further our understanding of visual pathologies associated with Parkinson's disease.