【摘要】 节律性（ｒｈｙｔｈｍｉｃｉｔｙ）是生命的基本特征之一，从单细胞生物到哺乳类动物的各种功能活动，生长繁殖乃至某些细微的形态结构，随着时间的推移都可能呈现某种有规律性的反复改变，这就是生物周期性，或生物节律性，亦称生物节律（ｂｉｏｌｏｇｉｃａｌｒｈｙｔ...更多还原

【Abstract】 Circadian rhythm is a general phenomenon in rodents, and it is a evolutionary result from animals’ environmental adaptation.The SCN (suprachiasmatic neucleus)is believed to be an oscillator in mammals. It has the ability of both generating endogenerous periodicity and synchronising the environmental factors. Gene experession of some IEGs (Immeadiate early qenes) in the SCN, e.g. c-fos, jun-B, is effected by photoperiod. Their experssion product, Fos-Jun, can regulate some clock genes’ expression. Thus, photoperiod can influent on circadian rhythm by speficially regulating genes’ expression.更多还原