Vera L M, De Oliveira C, López-Olmeda J F, Ramos J, Mañanós E, Madrid J A, Sánchez-Vázquez F J
Department of Physiology, Faculty of Biology, University of Murcia, 30100 Murcia, Spain.
J Pineal Res. 2007 Aug;43(1):50-5. doi: 10.1111/j.1600-079X.2007.00442.x.
The melatonin daily rhythm provides the organism with photoperiod-related information and represents a mechanism to transduce information concerning time of day. In addition, the duration and amplitude of the nocturnal elevation gives information about duration and thus the time of year. In this study, we investigate the existence of an annual rhythm of plasma melatonin in the Senegal sole. Differences in plasma melatonin levels between fish kept at a controlled temperature (17-20 degrees C) and those exposed to the environmental temperature cycle (11.5-25 degrees C) were also examined throughout the year. Spawning was registered in both groups to determine the time of year in which reproductive rhythms occurred. Our results pointed to the existence of an annual rhythm of plasma melatonin at mid-darkness (MD), with the highest levels (203 +/- 44 pg/mL) observed when water temperature reached 25 degrees C. Water temperature influenced nocturnal, but not diurnal melatonin. Daily melatonin rhythms showed seasonal differences, with higher mean nocturnal levels during the summer solstice (138 +/- 19 pg/mL) and autumn equinox (149 +/- 49 pg/mL). When animals were kept at a constant temperature throughout the year, plasma melatonin levels differed from those observed in fish exposed to the environmental temperature cycle. Regarding the reproductive rhythms, spawning was observed at the end of spring in sole kept under natural temperature conditions, whereas no spawning at all was registered in sole reared at a constant temperature. In short, both photoperiod and temperature affected melatonin production in the Senegal sole, transducing seasonal information and controlling annual reproductive rhythms.
褪黑素的每日节律为生物体提供与光周期相关的信息，并代表一种转导有关一天中时间信息的机制。此外，夜间升高的持续时间和幅度给出了关于持续时间以及一年中时间的信息。在本研究中，我们调查了塞内加尔鳎血浆褪黑素的年度节律的存在情况。全年还检查了饲养在可控温度（17 - 20摄氏度）下的鱼与暴露于环境温度周期（11.5 - 25摄氏度）下的鱼之间血浆褪黑素水平的差异。记录两组鱼的产卵情况以确定发生生殖节律的一年中的时间。我们的结果表明在午夜（MD）时存在血浆褪黑素的年度节律，当水温达到25摄氏度时观察到最高水平（203±44 pg/mL）。水温影响夜间褪黑素，但不影响白天的褪黑素。每日褪黑素节律呈现季节性差异，在夏至（138±19 pg/mL）和秋分（149±49 pg/mL）期间平均夜间水平较高。当动物全年保持在恒定温度下时，血浆褪黑素水平与暴露于环境温度周期的鱼中观察到的水平不同。关于生殖节律，在自然温度条件下饲养的鳎在春季末观察到产卵，而在恒定温度下饲养的鳎根本没有记录到产卵。简而言之，光周期和温度都影响塞内加尔鳎的褪黑素产生，转导季节性信息并控制年度生殖节律。
