Novel effects of light on central nervous system-Characteristics of non-visual photoactions and retinosuprachiasmatic complex

本研究表明，除了视觉之外，还有多种光对中枢神经系统的影响，这些影响是由视网膜和视网膜下丘脑束治疗的。对生物钟的影响主要分为两类：1)光作用：大鼠SCN中大多数多肽能神经元（AVP，VIP，SOM）是GABAnergic的，并且在5 -羟色胺剥夺后，SCN中VIPmRNA的表达具有节律性（Ibata）。在大鼠SCN切片培养中，视神经电刺激增加，钙离子消耗减少VIP分泌（柴田）。光在花栗鼠SCN中诱导Fos基因并不一定伴随着昼夜运动节律的相移（s.h honma）。大鼠衰老后Fos基因表达普遍降低，但光诱导Fos基因表达不受衰老影响（Yamaoka）。人类睡眠结构中的快速眼动睡眠倾向是通过突然改变明暗周期而系统改变的，这可能部分解释了时差综合征（Sasaki）。亮度超过500勒克斯的灯光抑制了人类夜间褪黑素的上升。但没有改变褪黑激素节律的阶段在携带条件下（k.h honma）。2)光对生物钟以外功能的作用：2- dg诱导的高血糖可通过给予VIP抗体阻断，SCN中的VIP神经元介导支配肝、肾和胸腺的自主神经的反应（Nagai）。强光刺激或减弱大鼠自主神经系统的神经元活动，增强免疫反应性，而这种作用被双侧SCN损伤所消除（Niijima）。仓鼠睾丸的光周期反应受营养状况和应激的影响（Ibuka）。年轻女性对寒冷的行为体温调节受到先前的强光照射和月经周期的影响（Tokura）。

The present study demonstrates a variety of light effects on the central nervous system other than vison, which are medicated by the retina and retinohypothalamic tract. The effects are divided essentially to two categories described as follows :1) Photic action on biological clock :Most peptidergic neuronsd (AVP,VIP,SOM) in the rat SCN were GABAnergic and arhythmic VIPmRNA expression in the SCN became rhythmic after serotonin deprivation (Ibata). Electrical stimulation of optic nerve increased and Ca ion deplivation decreased VIP secretion in the rat SCN slice culture (Shibata). Fos gene induction in the chipmunk SCN by light was not necessarily accompanied by phase-shifts of circadian locomotor rhythm (S.Honma.). Fos gene expression was generally decreased by aging in rats, but light-induced Fos expression was not altered significantly by aging (Yamaoka). REM sleep propencity in sleep structure was systematically changed in humans by changing the light-dark cycles abruptly, which may explain partly jet-lag syndrome (Sasaki). Lights brighter than 500 lux suppressed the nocturnal melatonin rise in humans. but did not shift the phase of melatonin rhythm under entrained condition (K.Honma).2) Photic action on functions other than biological clock :2-DG induced hyperglycemia was blocked by administration of VIP antibody, and VIP neurons in the SCN mediated the reaction to autonomic nerves innervating the liver, kidney and thymus (Nagai). Bright light stimulated or subsided the neuronal activities of autonomic nervous system in rats and enhanced immunoreactivity, which were abolished by bilateral SCN lesion (Niijima). Photoperiodic reactions of testis in hamsters are modified by nutritional state and stress (Ibuka). Behavioral thermoregulation to cold in young women is modifies by prior bright light exposure and menstrual cycle (Tokura).