LIGHT SUPPRESSION OF NOCTURNAL HUMAN MELATONIN SECRETION

褪黑激素（MT）几乎完全由松果体（PG）分泌， 晚上 我们以前的工作表明MT存在于人类中， 它的夜间分泌可以用明亮的人造光来抑制 （大于2000勒克斯）。 光的这种效应被认为是介导的 通过下丘脑连接视网膜和PG的神经通路。 在下丘脑水平，光的作用被认为是由 烟碱胆碱能受体 抑制MT是目前唯一的 下丘脑对光敏感指数。 我们已经证明人类 与实验动物相比，光MT效应的阈值较高。 例如，普通的人造光对人类似乎无效。 下丘脑对光的异常敏感性可能是一个重要的特征， 躁狂抑郁症的发病机制，季节性情感 睡眠时相延迟综合征 本项目的目的是（1）规范光MT抑制 检验（LMST），（2）确定LMST中的方差来源（年龄，性别， 先前的睡眠或清醒、先前的暴露于光等），（3） 研究下丘脑对光的敏感性使用LMST在 以上概述的疾病。 我们通过使用高强度的 钨丝灯 光谱质量由紫外线控制， - 红外滤光器，其修改投射到ganzfeld圆顶中的光，以及 通过使用中性密度滤光片来改变光的强度。 血液 在光施用之前、期间和之后获得样品。 使用 通过这些方法，可以生成LMST的注量-响应曲线， MT抑制程度表示为对数光强的函数 （瓦特/平方厘米）。

Melatonin (MT) is secreted by the pineal gland (PG) almost exclusively at night. Our previous work has shown that MT is present in humans and that its nocturnal secretion can be suppressed with bright artificial light (greater than 2000 lux). This effect of light is presumed to be mediated by neural pathways connecting the retina to the PG via the hypothalamus. At the hypothalamic level the effect of light is thought to be mediated by nicotinic cholinergic receptors. Suppression of MT is presently the only index of hypothalamic sensitivity to light. We have shown that humans have a high threshold for light-MT effects compared with experimental animals. Ordinary artificial light, for example, appears ineffective in humans. Abnormal hypothalamic sensitivity to light may be an important trait and pathogenic mechanism in manic-depressive illness, seasonal affective disorder and delayed sleep phase syndrome. The purpose of this project is (1) to standardize the light-MT suppression test (LMST), (2) to identify sources of variance in the LMST (age, sex, prior sleep or waking, prior exposure to light, etc.), and (3) to investigate hypothalamic sensitivity to light using the LMST in the disorders outlined above. We have standardized the administration of light by using high-intensity tungsten lamps. Spectral qualities are controlled by ultraviolet and infrared filters modifying the light projected into a ganzfeld dome, and intensities of light are varied by using neutral density filters. Blood samples are obtained before, during and after light administration. Using these methods a fluence-response curve for the LMST is being generated with the degree of MT suppression expressed as a function of log light intensity (watts/cm2).