FACTORS AFFECTING RETINAL SUSCEPTIBILITY OF DEGENERATION

拟议的研究旨在确定那些因素， 增加感光细胞对 退化 感光细胞的敏感性随着时间的推移而变化。 视网膜中年龄和（地形）位置的功能。 实验 是为了验证一个假设，即结构和化学变化 光感受器细胞的特性是它们的变化的基础。 易变性 光感受器特异性变性 是通过将老鼠的视网膜暴露在恒定的光线下产生的。 使用 形态测量和视网膜电图技术， 光诱导的变性将作为年龄的函数来确定， 视网膜区 其他几个参数，如棒外段 长度、盘堆积密度、更新速率、脂质与视蛋白比率以及 将在未暴露的动物中检查视紫红质浓度，也作为 年龄和视网膜区域的功能，以评估它们在影响 光感受器易变性。 一种检验感兴趣假设的新方法将利用孤立的 大鼠和蛙视网膜体外培养的扩展视网膜电图 录制. 视网膜将在含有以下物质的补充培养基中孵育 不同水平的营养素被认为可以保护感光细胞 退化 视网膜电图恶化引起的孵育与 将监测亚铁离子，随后将通过 显微镜 以这种方式，补充的营养素的能力， 改变感光细胞对退化的敏感性， 评估。 拟议的实验应有助于阐明 光感受器细胞对变性的敏感性及其 保护能力。 这些信息可能有助于努力 制定预防措施，防止类似的视网膜退化 人类的机制。

The proposed research seeks to identify those factors which are responsible for increases in the susceptibility of photoreceptor cells to degeneration. The susceptibility of photoreceptor cells varies as a function of age and (topographical) location in the retina. Experiments are designed to test the hypothesis that changes in structural and chemical properties of the photoreceptor cells underlie the variation in their susceptibility to degeneration. Photoreceptor-specific degeneration will be produced by exposing the retina of rats to constant light. Using morphometric and electroretinographic techniques, the severity of light-induced degeneration will be determined as a function of age and retinal region. Several other parameters, such as rod outer segment length, disk packing density, renewal rate, lipid to opsin ratio and rhodopsin concentration will be examined in non-exposed animals, also as a function of age and retinal region, to evaluate their role in influencing photoreceptor susceptibility to degeneration. A new approach to testing the hypothesis of interest will utilize isolated rat and frog retinas maintained in vitro for extended electroretinogram recording. Retinas will be incubated in supplemented media containing various levels of nutrients thought to protect against photoreceptor cell degeneration. Electroretinogram deterioration caused by incubation with ferrous ion will be monitored and retinas subsequently will be examined by microscopy. In this manner, the capability of supplemented nutrients in altering the susceptibility of photoreceptor cells to degeneration will be assessed. The proposed experiments should help to elucidate the basis for changes in both the susceptibility of photoreceptor cells to degeneration and their protective capability. This information could be helpful in efforts to devise preventative measures against retinal degenerations of similar mechanism in humans.