Department of Physiology, School of Medicine, İstanbul Medipol University, İstanbul, Turkey
Regenerative and Restorative Medicine Research Center (REMER), Research Institute for Health Sciences and Technologies (SABITA), İstanbul Medipol University, İstanbul, Turkey
Turk J Med Sci. 2020 Nov 3;50(SI-2):1655-1664. doi: 10.3906/sag-2008-32.
Apart from its metabolic or physiological functions, melatonin has a potent cytoprotective activity in the physiological and pathological conditions. It is synthetized by the pineal gland and released into the blood circulation but particularly cerebrospinal fluid in a circadian manner. It can also easily diffuse through cellular membranes due its small size and lipophilic structure. Its cytoprotective activity has been linked to its potent free radical scavenger activity with the desirable characteristics of a clinically- reliable antioxidant. Melatonin detoxifies oxygen and nitrogen-based free radicals and oxidizing agents, including the highly toxic hydroxyl-and peroxynitrite radicals, initiating cellular damage. However, the cytoprotective activity of melatonin is complex and cannot be solely limited to its free radical scavenger activity. It regulates cellular signaling pathways through receptor– dependent and independent mechanisms. Most of these downstream molecules, such as PI3K/AKT pathway components, also contribute to the cytoprotective effects of melatonin. In this term, melatonin is a promising molecule for the treatment of neurodegenerative disorders, such as ischemic stroke, which melatonin reduces ischemic brain injury in animal models of ischemic stroke. It regulates also circadian rhythm proteins after ischemic stroke, playing roles in cellular survival. In this context, present article summarizes the possible role of melatonin in the pathophysiological events after ischemic stroke.
除了其代谢或生理功能外，褪黑素在生理和病理条件下具有强大的细胞保护活性。它由松果体合成并以昼夜节律的方式释放到血液循环中，但特别是脑脊液中。由于其体积小和亲脂性结构，它也可以轻松地穿过细胞膜。其细胞保护活性与其强大的自由基清除活性有关，具有临床可靠抗氧化剂的理想特性。褪黑素可以解毒氧和氮自由基以及氧化剂，包括高度毒性的羟自由基和过氧亚硝酸盐自由基，从而引发细胞损伤。然而，褪黑素的细胞保护活性很复杂，不能仅仅局限于其自由基清除活性。它通过受体依赖和独立的机制调节细胞信号通路。这些下游分子中的大多数，如 PI3K/AKT 通路成分，也有助于褪黑素的细胞保护作用。在这种情况下，褪黑素是治疗神经退行性疾病（如缺血性中风）的有前途的分子，因为褪黑素可减少动物模型中的缺血性脑损伤。它还调节缺血性中风后的昼夜节律蛋白，在细胞存活中发挥作用。在这种情况下，本文总结了褪黑素在缺血性中风后病理生理事件中的可能作用。
