Prolonged Melatonin Synthesis During Long Nights: Mechanisms

松果体，一个连接到眼睛的小器官，位于 在大脑中心附近，产生一种激素， 重要的时间信息。 松果体 通过释放激素来完成这种计时功能 褪黑激素只在黑暗中进入血液。 正因如此， 白天血液中的褪黑激素水平很低， 在晚上高。 由于褪黑激素的昼夜变化， 身体中的器官被给予信息，即使没有连接 眼睛是明亮的，还是黑暗的。 当白昼长度 (and当然，夜长变化），例如在各种 一年四季，松果体的褪黑激素信息 也相应地改变。 生物学机制， 松果体能够释放高褪黑激素水平更长的时间 冬季的夜晚是未知的。 这样做的目的 研究是为了确定这是如何实现的。 问题是， 大脑是否“命令”松果体必须 还是松果体决定自己的命运 并调节褪黑激素释放的持续时间。 研究 本文将探讨这些问题。 收集到的信息 将适用于许多重要的生物学问题， 例如动物的季节性繁殖，羊毛的季节性变化 生长和产奶量，工作效率的每日变化， 了解“时差”和倒班工人的适应能力 新的时间表，以及了解条件，如 “冬季抑郁症”

The pineal gland, a small organ connected to the eyes and located near the center of the brain, produces a hormone that provides important timing information to the body. The pineal gland accomplishes this timing function by releasing the hormone melatonin into the blood only during darkness. Because of this, daytime levels of melatonin in the blood are low while they are high at night. Due to these day/night changes in melatonin, every organ in the body is given information, even though not connected to the eyes, as to whether it is light or dark. When day length (and of course night length change), such as during the various seasons of the year, the melatonin message from the pineal gland also changes accordingly. The biological mechanisms whereby the pineal gland is able to release high melatonin levels for longer periods during winter nights are unknown. The purpose of this research is to define how this is accomplished. The problem is, does the brain "dictate" to the pineal gland how long it must produce melatonin or does the pineal gland determine its own fate and regulate the duration of melatonin release. The studies outlined will examine these questions. The information garnered will be applicable to a number of important biological problems, e.g. seasonal reproduction in animals, seasonal variation in wool growth and milk production, daily variations in work efficiency, understanding "jet lag" and the ability of shift workers to adapt to new schedules, as well as understanding conditions such as "winter depression".