Morin L P
Department of Psychiatry, State University of New York at Stony Brook 11794.
J Biol Rhythms. 1993 Fall;8(3):189-97. doi: 10.1177/074873049300800302.
The pineal gland and its hormone, melatonin, have been implicated in the regulation of rat circadian rhythmicity. The present study was designed to evaluate whether the pineal has a similar role in the hamster, and to clarify whether the marked rhythm responses to constant light (LL) previously seen in serotonin-depleted hamsters might be attributable to a functional pinealectomy. The results demonstrated that young, but not old, hamsters showed loss of the circadian wheel-running rhythm (mostly via splitting) in LL, and that young hamsters had longer circadian periods in LL than old animals. Neither effect was related to the presence of a pineal gland. In LD 14:10 old animals ran much less than young animals, regardless of pineal status, and the suppression of running by LL was greater in old animals. The activity phase duration was only modestly related to age and not to pineal presence. The data support a previous report of an age effect on incidence of rhythm splitting and circadian period length, but do not support the view that the pineal gland helps modulate circadian rhythmicity in the hamster.
松果体及其激素褪黑素与大鼠昼夜节律的调节有关。本研究旨在评估松果体在仓鼠中是否具有类似作用，并阐明先前在血清素缺乏的仓鼠中观察到的对持续光照（LL）的明显节律反应是否可能归因于功能性松果体切除。结果表明，年幼而非年老的仓鼠在LL条件下出现昼夜节律性轮转行为丧失（主要通过分裂），且年幼仓鼠在LL条件下的昼夜周期比年老动物更长。这两种效应均与松果体的存在无关。在LD 14:10条件下，无论松果体状态如何，年老动物的活动量都比年幼动物少得多，且LL对年老动物活动的抑制作用更大。活动期持续时间仅与年龄有适度关联，与松果体的存在无关。这些数据支持了先前关于年龄对节律分裂发生率和昼夜周期长度有影响的报道，但不支持松果体有助于调节仓鼠昼夜节律的观点。
