Cardinali D P, Brusco L I, Cutrera R A, Castrillón P, Esquifino A I
Departamento de Fisiología, Facultad de Medicina, Universidad de Buenos Aires, Argentina.
Biol Signals Recept. 1999 Jan-Apr;8(1-2):41-8. doi: 10.1159/000014567.
Melatonin is synthesized and secreted during the dark period of the light/dark cycle. The rhythmic nocturnal melatonin secretion is directly generated by the circadian clock, located within the suprachiasmatic nuclei in mammals and is entrained to a 24-hour period by the light-dark cycle. The periodic secretion of melatonin may be used as a circadian mediator to any system that can 'read' the message. Melatonin seems to act as an arm of the circadian clock, giving a time-related signal to a number of body functions; one of these, the circadian organization of the defense of the organism, is discussed in some detail as an example.
褪黑素在光/暗周期的黑暗阶段合成并分泌。夜间褪黑素的节律性分泌直接由生物钟产生，生物钟位于哺乳动物的视交叉上核内，并通过明暗周期被调整为24小时周期。褪黑素的周期性分泌可作为一种昼夜节律调节因子作用于任何能够“读取”该信号的系统。褪黑素似乎起着生物钟分支的作用，向许多身体功能发出与时间相关的信号；作为一个例子，本文将详细讨论其中之一，即机体防御的昼夜节律组织。
