Inyushkin Alexey N, Poletaev Vitalii S, Inyushkina Elena M, Kalberdin Igor S, Inyushkin Andrey A
Department of Human & Animal Physiology, Samara National Research University, Samara 443011, Russia.
J Biomed Res. 2023 Dec 28;38(1):1-16. doi: 10.7555/JBR.37.20230133.
In mammals, the timing of physiological, biochemical and behavioral processes over a 24-h period is controlled by circadian rhythms. To entrain the master clock located in the suprachiasmatic nucleus of the hypothalamus to a precise 24-h rhythm, environmental zeitgebers are used by the circadian system. This is done primarily by signals from the retina the retinohypothalamic tract, but other cues like exercise, feeding, temperature, anxiety, and social events have also been shown to act as non-photic zeitgebers. The recently identified myokine irisin is proposed to serve as an entraining non-photic signal of exercise. Irisin is a product of cleavage and modification from its precursor membrane fibronectin type Ⅲ domain-containing protein 5 (FNDC5) in response to exercise. Apart from well-known peripheral effects, such as inducing the "browning" of white adipocytes, irisin can penetrate the blood-brain barrier and display the effects on the brain. Experimental data suggest that FNDC5/irisin mediates the positive effects of physical activity on brain functions. In several brain areas, irisin induces the production of brain-derived neurotrophic factor (BDNF). In the master clock, a significant role in gating photic stimuli in the retinohypothalamic synapse for BDNF is suggested. However, the brain receptor for irisin remains unknown. In the current review, the interactions of physical activity and the irisin/BDNF axis with the circadian system are reconceptualized.
在哺乳动物中，生理、生化和行为过程在24小时内的时间安排由昼夜节律控制。为了使位于下丘脑视交叉上核的主时钟与精确的24小时节律同步，昼夜节律系统利用环境授时因子。这主要通过来自视网膜的信号——视网膜下丘脑束来完成，但其他线索如运动、进食、温度、焦虑和社交活动也已被证明可作为非光授时因子。最近发现的肌动蛋白鸢尾素被认为是运动的一种同步非光信号。鸢尾素是其前体含Ⅲ型纤连蛋白结构域的膜蛋白5（FNDC5）在运动时经切割和修饰产生的产物。除了众所周知的外周效应，如诱导白色脂肪细胞“褐变”外，鸢尾素还能穿透血脑屏障并对大脑产生影响。实验数据表明，FNDC5/鸢尾素介导了体育活动对脑功能的积极作用。在几个脑区，鸢尾素可诱导脑源性神经营养因子（BDNF）的产生。在主时钟中，有人提出BDNF在视网膜下丘脑突触的光刺激门控中起重要作用。然而，鸢尾素的脑受体仍然未知。在当前的综述中，重新审视了体育活动以及鸢尾素/BDNF轴与昼夜节律系统之间的相互作用。
