NEURONAL PLASTICITY IN THE RETINA

这项研究项目是一项实验研究，试图了解 神经网络如何改变或适应环境的变化 刺激。在鱼的视网膜中，视锥细胞的光诱发反应 水平细胞，一种接受突触的二级细胞 锥体的接触，取决于周围的光照和昼夜节律 钟。生物钟是一种生物振荡器，具有 持续节律性，周期约为24小时 没有外部计时提示(例如，持续的黑暗)。此外，a 生物钟可以受到周期性环境刺激的影响，例如 灯。暗适应后，红色视锥输入到视锥水平细胞 白天占主导地位，杆输入占主导地位 夜里。因为这些影响在鱼身上观察到 持续的黑暗，因为光明/黑暗周期的先前反转 逆转这种影响，可以得出结论，生物钟调节 暗适应的影响。然而，昼夜节律因素 调节暗适应对锥体水平细胞的影响 也不知道逆转后影响时钟的因素 光明/黑暗的循环。 因此，电生理、神经化学和 解剖学技术将被用于研究昼夜节律 暗适应对金鱼视网膜影响的调节。它 将确定昼夜节律时钟是否调节锥体水平 细胞耦合，以及细胞内是否存在昼夜节律 视网膜神经递质、多巴胺和褪黑素水平，和/或 胞外pH。还将确定昼夜节律是否 在水平细胞中，光反应取决于多巴胺和 褪黑激素，以及细胞外pH的节律。最后，它将是 已确定多巴胺是否参与了时钟的夹带。这个 膜电位、光诱发反应和电与染料的耦合 在恒定的条件下，将研究锥形水平单元的大小 黑暗，使用超融合的，完整的视网膜准备。 视网膜生物钟过程的破坏可能起到调节作用。 感光细胞变性。因此，增加了对 昼夜节律时钟过程和途径以及递质功能将 有助于了解人类视网膜过程和功能障碍，如 为视网膜疾病的药物治疗提供依据。在……里面 此外，增加对多巴胺在视网膜中作用的了解可能会 帮助了解和治疗帕金森氏症。

This research project is an experimental study that seeks to understand how neuronal networks change or adapt to changes in environmental stimulation. In the fish retina, the light-evoked responses of cone horizontal cells, a type of second order cell that receives synaptic contact from cones, depend on the ambient illumination and on a circadian clock. A circadian clock is a type of biological oscillator that has persistent rhythmicity with a period of approximately 24 hours in the absence of external timing cues (e.g. constant darkness). In addition, a circadian clock can be entrained by cyclic environmental stimuli, such as light. Following dark adaptation, red cone input to cone horizontal cells predominates during the daytime and rod input predominates during the nighttime. Because these effects are observed in fish maintained in constant darkness and because prior reversal of the light/dark cycle reverses the effects, it can be concluded that a circadian clock regulates the effects of dark adaptation. However, the circadian factors that regulate the effects of dark adaptation on cone horizontal cells are not known, nor are the factors that entrain the clock following reversal of the light/dark cycle. Accordingly, a combination of electrophysiological, neurochemical and anatomical techniques will be used to investigate circadian rhythmic regulation of the effects of dark adaptation in the goldfish retina. It will be determined whether a circadian clock regulates cone horizontal cell coupling, as well as whether there are circadian rhythms in the levels of the retinal neurotransmitters, dopamine and melatonin, and/or in extracellular pH. It will also be determined whether the circadian rhythm in horizontal cell light responses depends on rhythms of dopamine and melatonin, as well as on a rhythm of extracellular pH. Finally, it will be determined whether dopamine is involved in entrainment of the clock. The membrane potential, light-evoked responses and electrical and dye coupling of cone horizontal cells will be studied under conditions of constant darkness, using a superfused, intact retina preparation. Disruption of circadian clock processes in the retina may mediate photoreceptor cell degeneration. Thus, increased understanding of circadian clock processes and pathways and of transmitter function will aid in the understanding of human retinal processes and dysfunction, as well as provide the basis for drug therapy for retinal disorders. In addition, increased knowledge of the action of dopamine in the retina may aid in the understanding and treatment of Parkinson's disease.