Departamento Fisiología (Fisiología Animal II), Facultad de Biología, Universidad Complutense de Madrid, Madrid, Spain.
Horm Behav. 2010 Mar;57(3):323-9. doi: 10.1016/j.yhbeh.2010.01.001. Epub 2010 Jan 15.
The present study focused on the effects of a subchronic melatonin treatment on locomotor activity and cortisol plasma levels in goldfish. We compared two different administration routes: peripheral (10 microg/g body weight) versus central (1 microg/microl) injections of melatonin for 7 or 4 days, respectively. Daily locomotor activity, including both diurnal and nocturnal activities, food anticipatory activity and circulating cortisol at 11:00 (under 24 h of food deprivation and 17 h postinjection) were significantly reduced after repeated intraperitoneal injections with melatonin for 7 days, but not after intracerebroventricular treatment. Taking in mind the anoretic effect of melatonin in this species, we investigated if such feeding reduction is directly responsible for the reduction in motor activity induced by melatonin treatment. Food restriction (50%) for 10 days did not significantly modify either daily locomotor activity or plasma cortisol levels in goldfish, indicating that the peripheral action of melatonin diminishing locomotor activity in goldfish is not a direct consequence of its anoretic action. In summary, our results indicate that, as previously described in other vertebrate species, melatonin can regulate locomotor activity and cortisol levels in goldfish, suggesting a sedative effect of this hormone in this teleost.
本研究主要关注亚慢性褪黑素处理对金鱼运动活动和皮质醇血浆水平的影响。我们比较了两种不同的给药途径：外周（10 微克/克体重）与中央（1 微克/微升）注射褪黑素，分别为 7 天和 4 天。每日运动活动，包括昼夜活动、食物预期活动和 11:00 时的循环皮质醇（在 24 小时禁食和 17 小时注射后），在重复腹膜内注射褪黑素 7 天后显著降低，但在脑室内治疗后没有降低。考虑到褪黑素在这种物种中的厌食作用，我们研究了这种摄食减少是否直接导致褪黑素处理引起的运动活动减少。10 天的 50%食物限制（食物限制）并没有显著改变金鱼的每日运动活动或血浆皮质醇水平，这表明褪黑素减少金鱼运动活动的外周作用不是其厌食作用的直接后果。总之，我们的结果表明，正如在其他脊椎动物物种中所描述的那样，褪黑素可以调节金鱼的运动活动和皮质醇水平，表明这种激素在这种硬骨鱼中具有镇静作用。
