Hudson R, Melo A I, González-Mariscal G
Institut für Medizinische Psychologie, Ludwig-Maximilians-Universität, München, Germany.
J Comp Physiol A. 1994 Nov;175(5):573-9. doi: 10.1007/BF00199478.
It was the purpose of this study to test whether inhibition of estrus in the rabbit by short photoperiod could be simulated by subcutaneous implants of the pineal hormone melatonin. By measuring two non-invasive and readily quantifiable correlates of estrus, emission of the so-called nipple-search pheromone and scent-marking behavior (chinning), it was found that: 1. In intact does kept in stimulatory long photoperiod, melatonin suppressed chinning but had no effect on emission of nipple-search pheromone. 2. In intact, melatonin-treated does which were returned from inhibitory short day to stimulatory long day, chinning remained suppressed, whereas pheromone emission increased as for the vehicle-treated, control does. 3. In ovariectomized does, estradiol administration stimulated both pheromone emission and chinning whereas melatonin failed to suppress these effects. Thus, although the administration of melatonin had an inhibitory effect on chinning it failed to suppress emission of the nipple-search pheromone and therefore failed to fully simulate the effect of short photoperiod on these two correlates of estrus. Several explanations for this discrepancy are considered, including the possibility that melatonin is not the sole mediary of the photoperiodic response, and that at least in female rabbits, other pineal products may also play a significant role.
本研究的目的是测试松果体激素褪黑素的皮下植入物是否能够模拟短光照周期对兔发情的抑制作用。通过测量发情的两个非侵入性且易于量化的相关指标，即所谓的乳头搜索信息素的释放和气味标记行为（蹭下巴），发现：1. 在处于刺激性长光照周期的完整母兔中，褪黑素抑制了蹭下巴行为，但对乳头搜索信息素的释放没有影响。2. 在经过褪黑素处理的完整母兔中，从抑制性短日照恢复到刺激性长日照后，蹭下巴行为仍然受到抑制，而信息素的释放则像接受载体处理的对照母兔一样增加。3. 在去卵巢的母兔中，给予雌二醇会刺激信息素的释放和蹭下巴行为，而褪黑素未能抑制这些作用。因此，尽管给予褪黑素对蹭下巴行为有抑制作用，但它未能抑制乳头搜索信息素的释放，因此未能完全模拟短光照周期对发情这两个相关指标的影响。本文考虑了对此差异的几种解释，包括褪黑素可能不是光周期反应的唯一介质，以及至少在雌性兔中，松果体的其他产物可能也起重要作用。
