Am J Psychiatry. 2013 Dec;170(12):1403-12. doi: 10.1176/appi.ajp.2013.13010111.
Research in the last century has demonstrated that light is a critical regulator of physiology in animals. More recent research has exposed the influence of light on human behavior, including the phenomenon of seasonal affective disorder (SAD). Repeated studies have shown that light treatment is effective in this disorder. The molecular mechanism by which the body absorbs the light that has energizing and antidepressant effects is still uncertain. This review presents evidence regarding the role of rod and cone photoreceptors, as well as the role of recently discovered nonvisual neuronal melanopsin-containing photoreceptors. The authors discuss an evolutionary-based theoretical model of humoral phototransduction. This model postulates that tetrapyrrole pigments, including hemoglobin and bilirubin, are blood-borne photoreceptors, regulating gasotransmitters such as carbon monoxide when exposed to light in the eye. Recent studies in an animal model for seasonality provide data consistent with this model. Understanding the molecular mechanisms by which light affects physiology may guide the development of therapies for SAD and other pathologies of circadian and circannual regulation.
上个世纪的研究表明，光对动物的生理机能具有关键性的调控作用。最近的研究揭示了光对人类行为的影响，包括季节性情感障碍（SAD）现象。反复的研究表明，光照疗法对此类疾病具有疗效。但目前仍不清楚人体吸收具有兴奋和抗抑郁作用的光线的分子机制。本文综述了视杆细胞和视锥细胞、以及最近发现的含有黑视蛋白的非视觉神经元感光细胞的作用的相关证据。作者还讨论了基于体液光传导的进化理论模型。该模型假设包括血红蛋白和胆红素在内的四吡咯色素是血液感光器，当它们在眼睛中暴露于光时，会调节一氧化碳等气体递质。季节性动物模型的最新研究提供了与该模型一致的数据。了解光影响生理机能的分子机制可能有助于为 SAD 及其他昼夜节律和年周期调节相关病变的治疗提供指导。
