Jilge B
Laboratory Animals Research Unit, University of Ulm, Germany.
J Biol Rhythms. 1993 Fall;8(3):247-60. doi: 10.1177/074873049300800307.
The nursing rhythms of 14 rabbit does and the activity of 18 litters from birth to days 14-16 were monitored continuously, as were the circadian rhythms of different behavioral functions of 10 young rabbits from weaning until day 380 of life. The does gave birth 2 hr, 26 min +/- 2 hr, 8 min after lights-on in a light-dark cycle (LD 12:12). The first nursing occurred 20 hr, 30 min +/- 2 hr, 21 min after parturition. Does that had continuous access to the next boxes exhibited a regular once-a-day nursing rhythm; the nursing visits to the litters occurred during the dark phase (D). The nursing visits lasted 3 min, 42 sec +/- 25 sec. Nursing advanced during the first 10 days of lactation by an average of 42 +/- 16 min/day, and thus shifted to the first half of D. The pups anticipated nursing by a significant increase of activity, which was established between days 1 and 5 of life. In two does, the nursing rhythm split into two nursing visits per day, one during D and one during the light phase (L). When scheduled to nurse at an "artificial" phase in L with T = 24 hr, the pups' anticipatory activity was entrained by the 24-hr nursing rhythm. During a 48-hr fast, the elevated activity persisted around the phase of prior nursing time, demonstrating that it was controlled by an endogenous oscillator entrained by the zeitgeber of maternal nursing. Of 10 weanlings, 6 first exhibited a trimodal rhythm, which turned bimodal within 3-6 days. Stable entrainment by the external LD zeitgeber was attained by about days 45-80, and full nocturnality was attained by about days 200-250 after weaning. Having attained steady-state conditions, 7 of 10 rabbits exhibited a stable unimodal, nocturnal rhythm in each of the five functions, while the other 3 retained a bimodal rhythm.
对14只母兔的哺乳节律以及18窝幼兔从出生到第14 - 16天的活动进行了连续监测，同时也对10只幼兔从断奶到生命第380天不同行为功能的昼夜节律进行了监测。母兔在明暗周期（LD 12:12）中光照开启后2小时26分钟±2小时8分钟分娩。第一次哺乳发生在分娩后20小时30分钟±2小时21分钟。能够持续进入相邻产箱的母兔表现出规律的每日一次哺乳节律；对幼兔的哺乳访问发生在黑暗阶段（D）。哺乳访问持续3分钟42秒±25秒。在哺乳期的前10天，哺乳时间平均每天提前42±16分钟，从而转移到黑暗阶段的前半段。幼兔通过活动显著增加来预期哺乳，这种现象在出生后第1至5天形成。在两只母兔中，哺乳节律分为每天两次哺乳访问，一次在黑暗阶段，一次在光照阶段（L）。当安排在光照阶段以24小时的“人工”阶段进行哺乳时，幼兔的预期活动被24小时的哺乳节律所调节。在48小时禁食期间，较高的活动在先前哺乳时间的阶段附近持续存在，表明它是由母性哺乳的时间信号所调节的内源性振荡器控制的。在10只断奶幼兔中，6只最初表现出三峰节律，在3 - 6天内转变为双峰节律。在大约第45 - 80天通过外部LD时间信号实现稳定调节，断奶后大约第200 - 250天达到完全夜行性。在达到稳态条件后，10只兔子中有7只在五种功能中的每一种都表现出稳定的单峰夜行节律，而另外3只则保持双峰节律。
