Photic and Circadian Regulation of Retinal Melatonin

描述（由申请人提供）：哺乳动物视网膜含有生物钟，其通过驱动基因表达、光感受器外节膜更新和视觉敏感性的昼夜节律来调节视网膜功能的多个方面。我们的长期目标是了解光和昼夜节律钟如何控制视网膜和中枢神经系统功能，以及这种光和昼夜节律控制的中断对神经元，特别是感光细胞的健康和活力的影响。我们的假设是，一个层次网络的时钟调节昼夜节律的哺乳动物视网膜和起搏器控制褪黑激素的合成是主昼夜节律钟。此外，我们认为褪黑激素在光感受器的活力和功能中起重要作用。在过去的几个月里，我们已经开发了一种独特的体外制剂和一系列转基因小鼠，其中褪黑激素在视网膜中的作用可以进行测试。设计了三个具体目标来检验这一假设。在具体目标1中，我们将确定小鼠光感受器是否包含驱动褪黑激素合成的昼夜节律起搏器。在具体目标2中，我们将通过比较C3 H/f+/+中的褪黑激素熟练小鼠（C3 H/f+/+）和褪黑激素受体敲除小鼠（MT 1-/-、MT 2-/-和MT 1-/-MT 2-/-）来研究褪黑激素在视网膜节律性产生中的作用。最后，在具体目标3中，我们将使用C3 H/f+/+背景中的褪黑激素受体敲除小鼠来测试褪黑激素对于光感受器功能和活力是重要的假设。在我们的研究中，我们将使用广泛的新技术和先进技术，例如定量真实的RT-PCR、激光捕获解剖显微镜、微阵列分析以及实时监测光感受器层或分离的光感受器中的生物发光节律性。意义视网膜生物钟参与视网膜生理的许多方面的调节。因此，了解视网膜时钟功能的细胞和分子基础将大大提高我们对视网膜生理学和病理学的认识。现代生活方式极大地改变了我们暴露于光的时间;因此，了解这种暴露可能对视网膜生理学和病理学的影响是很重要的。

DESCRIPTION (provided by applicant): The mammalian retina contains circadian clocks that regulate multiple aspects of retinal function by driving circadian rhythms of gene expression, photoreceptor outer segment membrane turnover, and visual sensitivity. Our long term goal is to understand how light and the circadian clocks control retinal and central nervous system functions, and the effects that disruption of this photic and circadian control has on the health and viability of neurons, especially photoreceptor cells. Our hypothesis is that a hierarchical network of clocks regulates circadian rhythms in the mammalian retina and the pacemaker controlling melatonin synthesis is the master circadian clock. Furthermore, we believe that melatonin plays and important role in photoreceptors viability and functioning. In the last few months we have developed a unique in vitro preparation and a series of transgenic mice in which the role of melatonin in the retina can be tested. Three specific aims are designed to test this hypothesis. In specific aim 1, we will determine if mouse photoreceptors contain the circadian pacemaker that drives melatonin synthesis. In Specific aim 2, we will investigate the roles of melatonin in the generation of retinal rhythmicity by comparing melatonin proficient mice (C3H/f+/+) and melatonin receptor knock-out mice (MT1-/-, MT2-/- and MT1-/-MT2-/-) in C3H/f+/+. Finally, in specific aim 3 we will use melatonin receptor knock-out mice in C3H/f+/+ background to test the hypothesis that melatonin is important for photoreceptor functioning and viability. In our research, we will use a wide array of new and technologically advanced techniques, such as quantitative real time RT-PCR, laser capture dissecting microscopy, microarray analysis as well as real-time monitoring of bioluminescence rhythmicity in photoreceptor layers or isolated photoreceptor. Significance. Retinal circadian clock are involved in the modulation of many aspects of retinal physiology. Thus, understanding the cellular and molecular basis of retinal clock function will greatly improve our knowledge of retinal physiology and pathologies. Modern life style has tremendously changed the time at which we expose ourselves to light; hence, it is important to understand the effect that such exposure may have on retinal physiology and pathology.