INTERCELLULAR COMMUNICATION IN RETINAL DEVELOPMENT

神经元连接的有组织模式是如何在生命早期发展起来的 神经系统发育中的基本问题。 视网膜中神经元之间的交流甚至发生在 光感受器对光做出反应。这导致了协调的模式 活动，可以指导在 视网膜，以及视网膜和大脑中的视觉中心之间。如果没有 在神经连接如此精确的情况下，视觉图像处理可能永远 达到成年的成熟和成熟程度。这项建议 解决协调活动和细胞间通信的作用 在出生后早期的雪貂的视网膜中。 在第一个项目中，体外细胞内钙的变化将是 用于监测自发激发波如何导致 不同类型神经元之间的活动相关性，以及 新生雪貂视网膜的不同区域。现役人员的身份 细胞将通过结合Fura-2成像和细胞内染料- 填饱肚子。将从分离的细胞中进行录音，以便 确定视网膜细胞的节律性爆裂活动是否是 细胞的生理属性，而不是细胞网络。这个 神经递质释放和缝隙连接在介导神经递质损伤中的作用 波的传播将使用药物进行评估，以 扰乱电波，并在细胞内注入一种示踪剂 缝隙连接，以确定共激活细胞是否为细胞间连接 结合在一起。 中枢神经系统神经递质及其受体的早期出现 视网膜提示这些分子在视网膜发育中起作用。 结构和功能。在第二个项目中，我们希望确定 神经递质是否在脑内神经元之间的局部通讯中起中介作用 新生儿视网膜，其方式可能对突触有指导意义 队形。急性新生儿视网膜切片、无长突细胞和双极细胞 会受到刺激，它们的细胞内钙水平 邻居将受到光学监控。细胞所使用的手段 通信(发射器与缝隙连接)将使用 药理药物和细胞内神经生物素(一种示踪剂 交叉缝隙连接)注射。在第三个项目中，互动 将研究新生雪貂脑室带细胞的数量。在……里面 特别是，M胆碱能受体在细胞内的作用 细胞间信号传递将进行药理学研究。这个 这些相互作用对细胞增殖的结果将被确定 通过检测体内注射M受体是否 拮抗剂可减少有丝分裂。 通过监测大量动物之间的生理互动 发展视网膜神经元，我们希望能更好地了解 这些相互作用可能导致形成精确的联系 视网膜，以及视网膜与其中心靶点之间。此外， 这些实验将加深我们对什么是共同的 采取各种策略确保神经元的正常发育。 中枢神经系统的通路。

How organized patterns of neuronal connections develop early in life is a fundamental question in the development of the nervous system. Communication between neurons in the retina occurs even before the photoreceptors respond to light. This leads to patterns of coordinated activity which can guide the development of precise connections within the retina, and between the retina and visual centers in the brain. Without such precision in neural connectivity, visual image processing may never reach its adult level of maturity and sophistication. This proposal addresses the role of coordinated activity and intercellular communication in the retina of the early postnatal ferret. In the first project, changes in intracellular calcium in vitro will be used to monitor how spontaneous waves of excitation may lead to correlations in activity among neurons of various types, and across various regions of the neonatal ferret retina. The identity of the active cells will be obtained by combining Fura-2 imaging with intracellular dye- filling. Recordings from dissociated cells will be made in order to determine whether the rhythmic bursting activity of retinal cells is a physiological property of the cell, rather than the network of cells. The role of neurotransmitter release and gap junctions in mediating the propagation of the waves will be assessed using pharmacological agents to disrupt the waves, and intracellular injection of a tracer that crosses gap junctions, to determine whether coactive cells are intercellularly coupled. The early appearance of neurotransmitters and their receptors in the retina suggests a role for these molecules in the development of retinal structure and function. In the second project, we wish to determine whether transmitters mediate local communication between neurons of the neonatal retina, in a manner which could be instructive for synapse formation. In acute neonatal retinal slices, amacrine and bipolar cells will be stimulated, and the intracellular calcium levels of their neighbors will be monitored optically. The means by which the cells communicate (transmitters versus gap junctions) will be assessed using pharmacological agents and intracellular Neurobiotin (a tracer which crosses gap junctions) injections. In the third project, the interactions of cells in the ventricular zone of neonatal ferrets will be studied. In particular, the role of muscarinic cholinergic receptors in intracellular and intercellular signaling will be examined pharmacologically. The outcome of these interactions on cellular proliferation will be determined by examining whether in vivo intraocular injections of muscarinic receptor antagonists reduces mitosis. By monitoring the physiological interactions between large numbers of developing retinal neurons, we hope to gain a better understanding of how these interactions might lead to the formation of precise connections of the retina, and between the retina and its central targets. Furthermore, these experiments would enhance our understanding of what common strategies are employed to ensure the normal development of neuronal pathways in the central nervous system.