AMACRINE CELL FUNCTION IN THE RETINA

无长突细胞是视网膜近端的侧向中间神经元 它们位于战略位置，以影响 神经节细胞。因此，无长突细胞在决定 由视网膜的最终输出路径携带的视觉信息 更高级的大脑中心。尽管视网膜无长突细胞一直是 许多形态和药理研究的主题，许多 我们对哺乳动物中无长突细胞功能的了解已经获得 间接来自针对神经节细胞的工作或从研究中推断 属于低等脊椎动物。绝大多数视网膜神经递质， 包括多肽，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 的神经递质将定位于由 无长突细胞。不幸的是，无长突细胞的生理学，以及 因此，其中许多发射器的功能目前尚不清楚。 这项研究的长期目标是确定生理学 哺乳动物视网膜中无长突细胞表达的反应特性 并将它们与它们的形态联系起来。实验性的 战略不仅仅是确定存在于 无长突细胞的结构和功能还可形成生理性 结合现有的形态和药理作用的框架 数据。使用的基本方法是从神经元的细胞内记录 兔眼用的超融合的视网膜眼球制剂。 生理特征的细胞随后被标记为 细胞内辣根过氧化物酶(HRP)染色检测 它们的胞体树枝状形态。最近的研究结果表明， 无长突细胞表现出比想象中更丰富的反应 以前，如方位和方向敏感度。因此， 拟议研究的具体目标侧重于复杂反应 无长突细胞的特性及其产生。这些措施包括：(1) 胆碱能星爆型长春花碱的方向性测定 细胞及其产生的机制。(2)审查 定向敏感型Ae型水平仪之间的电耦合 在兔的偏向的无长突细胞和细胞之间。 这一系列研究将确定电突触是否 并扩展这些单元格的方向敏感度 广阔的接受场。(3)研究材料的取向敏感性。 兔的双极细胞，以确定它们是否可以提供途径 用于从水平方向传递方向敏感的视觉信息 到无长突细胞。(4)研究主动传播的作用 突触输入在形成无长突细胞感受野中的作用。

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.