Transmembrane proteins known as hyperpolarization-activated cyclic nucleotide-gated (HCN) channels control the movement of Na+ and K+ ions across cellular membranes. HCN channels are known to be involved in crucial physiological functions in regulating neuronal excitability and rhythmicity, and pacemaker activity in the heart. Although HCN channels have been relatively well investigated in the brain, their distribution and function in the retina have received less attention, remaining their physiological roles to be comprehensively understood. Also, because recent studies reported HCN channels have been somewhat linked with the dysfunction of photoreceptors which are affected by retinal diseases, investigating HCN channels in the retina may offer valuable insights into disease mechanisms and potentially contribute to identifying novel therapeutic targets for retinal degenerative disorders. This paper endeavors to summarize the existing literature on the distribution and function of HCN channels reported in the vertebrate retinas of various species and discuss the potential implications for the treatment of retinal diseases. Then, we recapitulate current knowledge regarding the function and regulation of HCN channels, as well as their relevance to various neurological disorders.

中文翻译：

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跨物种脊椎动物视网膜中超极化激活的环核苷酸门控通道的定位及其生理作用

称为超极化激活环核苷酸门控 (HCN) 通道的跨膜蛋白控制 Na 的运动+和K+离子穿过细胞膜。众所周知，HCN 通道参与调节神经元兴奋性和节律性以及心脏起搏器活动的重要生理功能。尽管 HCN 通道在大脑中的研究相对较好，但它们在视网膜中的分布和功能受到的关注较少，其生理作用仍有待全面了解。此外，由于最近的研究报道 HCN 通道与受视网膜疾病影响的光感受器功能障碍有一定联系，因此研究视网膜中的 HCN 通道可能为了解疾病机制提供有价值的见解，并可能有助于确定视网膜退行性疾病的新治疗靶点。本文致力于总结有关不同物种脊椎动物视网膜中 HCN 通道分布和功能的现有文献，并讨论其对视网膜疾病治疗的潜在影响。然后，我们概括了有关 HCN 通道的功能和调节及其与各种神经系统疾病的相关性的当前知识。