STRUCTURE AND FUNCTION IN RETINAL NEURONS

视网膜神经元对神经递质表达独特的反应。谷氨酸既有兴奋也有抑制。GABA的反应通常是拮抗剂不敏感的。该项目的目标是1)研究视网膜神经元对外源性药物刺激和自然光刺激的反应，以及2)了解视网膜神经元上受体表达、视网膜神经回路和视网膜信息处理任务之间的关系。这项研究检查了大鼠和斑马鱼急性分离的视网膜神经元，以及斑马鱼视网膜切片中发现的原位神经元。急性分离的双极细胞和水平细胞保持其形状，并可在培养中从形态上进行鉴定。视网膜切片中的细胞通过记录电极注入细胞内染料进行形态鉴定。用电压敏感探针检测分离细胞的生理反应；采用全细胞膜片钳技术记录视网膜切片中神经元的反应。通过基于互联网的教程Webvision传播视网膜神经生物学知识仍然是该项目的一个辅助目标。斑马鱼双极细胞树突上的谷氨酸受体类型在视网膜切片和局部喷雾的全细胞膜片钳记录中被鉴定为四种类型：1.推测脱离双极的电导增加(EREV~0 mV)。这种反应是红藻氨酸敏感的，CNQX被阻断。2.假定在双极上有类APB电导下降(EREV~0 mV)。3.推测在双极上谷氨酸门控的氯离子电导增加。4.假定为双极的机制2和3的组合。无双极细胞对NMDA有反应。一个双极细胞轴突总是出现在与推测的反应极性相适应的开或离内丛状层亚板中，尽管在两个亚板中许多轴突与突起呈多层分布。这些发现表明，在斑马鱼的双极细胞中，谷氨酸传导机制的多样性产生光反应，而在内丛状层亚胺a和b-GABA、谷氨酸、视网膜、双极细胞、神经回路、大鼠、斑马鱼、Webvision中可能存在开和关信号输入的混合

Retinal neurons express unique responses to neurotransmitters. Glutamate both excites and inhibits.GABA responses are commonly antagonist-insensitive. The project goals are 1) to study responses of retinal neurons to exogenous pharmacological stimuli, as well as natural light stimuli, and 2) to understand the relationships between receptor expression on retinal neurons, the neural circuitry of retina, and retinal information-processing tasks. The study examines acutely dissociated retinal neurons from rat and zebrafish, and in-situ neurons identified in zebrafish retinal slices. Acutely dissociated bipolar and horizontal cells retain their shapes and can be morphologically identified in culture. Cells in retinal slices are identified morphologically by intracellular dye injection via the recording electrode. Physiological responses of isolated cells are assayed with voltage-sensitive probes; whole-cell patch clamp techniques are used to record the responses of neurons in the retinal slice. Dissemination of knowledge in retinal neurobiology through WEBVISION, an internet-based tutorial, continues to be a subsidiary goal of this project. Four glutamate-receptor types were identified on zebrafish bipolar-cell dendrites with whole-cell patch clamp recordings in retinal slice and localized puffs: 1. A conductance increase (Erev ~ 0mV) in presumed OFF bipolars. Such responses were kainate sensitive and CNQX blocked. 2. An APB-like conductance decrease (Erev ~ 0mV) in presumed ON bipolars. 3. A glutamate-gated chloride conductance increase in presumed ON bipolars. 4. A combination of mechanisms 2 and 3 in presumed ON bipolars. No bipolars responded to NMDA. One bipolar-cell axonal bouton always occurred in the ON or OFF inner-plexiform-layer sublamina appropriate to the presumptive response polarity, though many axons were multistratified with boutons in both sublaminae. These findings indicate a diversity of glutamate conductance mechanisms generate the light responses in zebrafish ON-, but not OFF-, bipolar cells, and that there likely is mixing of ON and OFF signal inputs in inner-plexiform- layer sublaminas a and b. - GABA, Glutamate, Retina, Bipolar, cells, neural circuits, rat, zebrafish, webvision