Rea M A
Biological Rhythms and Integrative Neuroscience Institute, Air Force Research Laboratory, Brooks AFB, Texas, USA.
Chronobiol Int. 1998 Sep;15(5):395-423. doi: 10.3109/07420529808998699.
Photic entrainment of circadian rhythms occurs as a consequence of daily, light-induced adjustments in the phase and period of the suprachiasmatic nuclei (SCN) circadian clock. Photic information is acquired by a unique population of retinal photoreceptors, processed by a distinct subset of retinal ganglion cells, and conveyed to the SCN through the retinohypothalamic tract (RHT). RHT neurotransmission is mediated by the release of the excitatory amino acid glutamate and appears to require the activation of both NMDA- and non-NMDA-type glutamate receptors, the expression of immediate early genes (IEGs), and the synthesis and release of nitric oxide. In addition, serotonin appears to regulate the response of the SCN circadian clock to light through postsynaptic 5-HT1A or 5-ht7 receptors, as well as presynaptic 5-HT1B heteroreceptors on RHT terminals.
昼夜节律的光驱动是由于视交叉上核（SCN）生物钟的相位和周期每日受光诱导调整的结果。光信息由独特的视网膜光感受器群体获取，经特定的视网膜神经节细胞子集处理，并通过视网膜下丘脑束（RHT）传递至SCN。RHT神经传递由兴奋性氨基酸谷氨酸的释放介导，似乎需要NMDA型和非NMDA型谷氨酸受体的激活、即刻早期基因（IEG）的表达以及一氧化氮的合成与释放。此外，血清素似乎通过突触后5-HT1A或5-HT7受体以及RHT终末上的突触前5-HT1B异受体来调节SCN生物钟对光的反应。
