模拟空间节律(L:D=0.75h:0.75h)对树鼩(Tupaia belangeri chinensis)“24h 昼夜节律”的影响

EFFECTS OF SIMULATED SPACE RHYTHM(L:D=0.75h:0.75h)ON CIRCADIAN RHYTHM IN TREE SHREWS(TUPAIA BELANGERI CHINENSIS)

模拟地球外层空间400—500km 处的空间节律(L:D=0.75h:0.75h)显著打乱灵长类原宗树鼩(Tupaia belangeri chinensis)固有的昼夜节律。其表现为晨间活动量的最高峰(0600—1200显著跌落,而在晚间(1800—2400)出现活动量显著增高的新峰,24h 活动总量(A)的显著降低和恢复缓慢。本研究又表明给予上述空间节律前两天和给予空间节律期间的每天清晨(0600)或傍晚(1800)注射纯 α 型内源性促眠神经肽 Asp^5-α-DSIP(30μg/kg,i.p.),虽固有节律被打乱,但未见 A 的显著降低,同时恢复也较快。

It is known that contemporary space station revolves at the altitude of 400—500 km in the outer space.The present study was undertaken to investigate theeffects of simulated space rhythm(L:D=0.75 h:0.75 h)at this altitude on circadianrhythm in tree shrews(Tupaia belangeri chinensis)and the effects of endogenoussleep inducing neuropeptide Asp^5-α-DSIP on the space-rhythm-entrained circadianrhythm.This primitive stock serves as one species of Tupaiidae and is a uniquenative of South China.Our previous studies have shown that this species showedstriking differences in natural circadian rhythm between day and night(e.g.3.03℃of rectal temperature).Results showed that the above mentioned space rhythm(L:D=0.75h:0.75h)could drastically disturb the inherent circadian rhythm of Tupaia belangeri chinensis.The maximal peak of motor activity dropped significantly in the morning(0600—1200)and a new enhanced peak(more than 20 times greater than that of the con-trol)was found between 1800—2400,whereas the maximal trough of motor activity(2400—0600)remained basically unchanged.Concurrently,the total amount of 24-hmotor activity was significantly decreased and the recovery after the cessation ofspace rhythm was slow.Experimental results also demonstrated that consecutive administration ofAsp^5-α-DSIP(30 μg/kg,i.p.)for 5 days(2 days before and 3 days during spacerhythm)did not prevent the basic disturbance of circadian rhythm of Tupaia belangerichinensis caused by the space rhythm (L:D=0.75h:0.75h).Nevertheless,no decreaseor even some enhancement of the total amount of 24-h motor activity was observedduring space rhythm or after its cessation.