AMACRINE CELL FUNCTION IN THE RETINA

无长突细胞是位于近端视网膜的侧向中间神经元 其被战略性地定位以影响 神经节细胞 因此，无长突细胞在决定细胞的增殖和分化中起着关键作用。 由视网膜的最终输出路径携带的视觉信息， 更高的大脑中心 虽然视网膜无长突细胞一直是 许多形态学和药理学研究的主题， 我们对哺乳动物无长突细胞功能的了解已经达到 间接来自针对神经节细胞的工作或从研究中推断 低等脊椎动物的 绝大多数视网膜神经递质， 包括肽，被无长突细胞用来影响神经节细胞 活动 因此，视网膜病变很可能是由不平衡引起的， 神经传递素会被定位在 无长突细胞 不幸的是，无长突细胞的生理学， 因此，这些发射机中的许多发射机的功能目前还不清楚。 这项研究的长期目标是确定生理 哺乳动物视网膜无长突细胞的反应特性 并将其与它们的形态相关联。 实验 战略不仅是确定存在的相关性， 无长突细胞的结构和功能，而且还形成一个生理 将现有的形态学和药理学 数据 所用的基本方法是细胞内记录神经元， 灌注的兔子视网膜眼杯制剂。 生理学表征的细胞随后用 细胞内染色，如辣根过氧化物酶（HRP），以确定 它们的胞体-树突形态。 最近的研究结果表明， 无长突细胞的反应比想象的要丰富得多 以前，如方向和方向的敏感性。 因此 拟议研究的具体目标侧重于复杂的反应， 无长突细胞的性质及其生成。 这些措施包括：（1） 确定胆碱能星爆无长突的方向敏感性 细胞及其产生机制。(2)审查 方位敏感AE型水平 细胞和取向偏性无长突细胞之间的关系。 这一系列的研究将确定电突触是否 并扩大这些细胞的方向敏感性， 广泛的接受域(3)为了研究定向敏感性， 双极细胞，以确定它们是否可以提供 用于从水平方向通过对方向敏感的视觉信息 到无长突细胞(4)为了研究积极传播的作用， 突触输入在形成无长突细胞的感受野。

Amacrine cells are laterally-oriented interneurons in the proximal retina which are located strategically to influence the response properties of ganglion cells. Thus, amacrine cells play a key role in determining the visual information carried by the final output pathway of the retina to higher brain centers. Although retinal amacrine cells have been the subject of numerous morphological and pharmacological studies, much of our knowledge of amacrine cell function in the mammal has been attained indirectly from work directed at ganglion cells or inferred from studies of lower vertebrates. The vast majority of retinal neurotransmitters, including peptides, are used by amacrine cells to affect ganglion cell activity. It is likely, then, that retinopathies derived from imbalances of neurotransmitters would be localized to circuitry subserved by amacrine cells. Unfortunately, the physiology of amacrine cells, and thus the function of many of these transmitters, is presently unclear. The long term goal of this research is to determine the physiological response properties expressed by amacrine cells in the mammalian retina and to correlate these with their morphologies. The experimental strategy is not only to determine the correlations that exist between amacrine cell structure and function but also to form a physiological framework to incorporate the available morphological and pharmacological data. The basic method used is intracellular recording from neurons in the superfused, retina-eyecup preparation of the rabbit. Physiologically-characterized cells are subsequently labeled with intracellular stains such as horseradish peroxidase (HRP) to determine their soma-dendritic morphologies. Recent findings indicate that amacrine cells show a much richer variety of responses than thought previously, such as orientation and direction sensitivity. Thus, the specific aims of the proposed research focus on complex response properties of amacrine cells and their generation. These include: (1) To determine the direction sensitivity of the cholinergic starburst amacrine cells and the mechanism underlying its generation. (2) To examine electrical coupling between the orientation-sensitive Ae-type horizontal cells and between the orientation-biased amacrine cells in the rabbit. This line of research will establish whether electrical synapses preserve and expand the orientation sensitivity of these cells across their extensive receptive fields. (3) To study the orientation sensitivity of bipolar cells in the rabbit to determine if they may provide the route for passage of orientation-sensitive visual information from horizontal to amacrine cells. (4) To examine the role of active propagation of synaptic inputs in shaping the receptive fields of amacrine cells.