Lack of circadian regulation of in vitro melatonin release from the pineal organ of salmonid teleosts
Lack of circadian regulation of in vitro melatonin release from the pineal organ of salmonid teleosts
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DOI：
10.1016/j.ygcen.2007.06.013
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发表时间：
2007-10-01
影响因子：
2.7
通讯作者：
Yanagisawa, Tadashi
中科院分区：
文献类型：
--
作者：
Iigo, Masayuki;Abe, Tomotaka;Yanagisawa, Tadashi
在许多硬骨鱼物种中，感光松果体器官具有调节松果体器官本身褪黑激素释放的生物钟。然而，三种鲑鱼（虹鳟Oncorhynchus mykiss、马苏鲑鱼Oncorhynchus masou 和红鲑Oncorhynchus nerka）的松果体器官在体外维持在持续黑暗的条件下时，褪黑激素的释放并未表现出昼夜节律（1313），这表明所有鲑鱼的松果体器官缺乏褪黑激素产生的昼夜节律调节。为了验证这一假设，我们研究了七种鲑科鱼类（普通白鲑 Coregonus lavaretus、河鳟 Thymallus thymallus、日本 huchen Hucho perryi、日本红点鲑 Salvelius leucomaenis pluvius、溪鳟 Salvelius fontinalis、褐鳟 Salmo trutta 和鲑鱼 Oncorhynchus keta）和密切相关的奥斯鱼（香鱼 Plecoglossus）的松果体器官。 altivelis altivelis 和日本胡瓜鱼 Hypomesus nipponensis) 分别在 15 摄氏度和多种光照条件下进行流过培养。在明暗循环下，所有物种的松果体在黑暗阶段都表现出有节奏的褪黑激素高速率释放。在DD下，奥斯鱼松果体器官仅在主观夜间以高速率释放褪黑激素，表现出昼夜节律，但鲑鱼松果体器官持续以高速率释放褪黑激素。在持续光照下，所有物种的褪黑激素释放均受到抑制。虹鳟鱼的松果体器官维持在不同的温度下（DD下的15、20或25℃，褪黑激素的释放率很高，但褪黑激素的释放量对温度敏感（20℃时最高）。因此，奥斯鳉松果体器官的褪黑激素释放受到光和生物钟的调节，但鲑鱼缺乏昼夜节律调节。这些结果表明，祖先鲑鱼失去了褪黑激素的调节能力。硬骨鱼分化后褪黑素产生的昼夜节律调节 (C) 2007 Elsevier Inc. 保留所有权利。
In many teleost species, the photoreceptive pineal organ harbors the circadian clock that regulates melatonin release in the pineal organ itself. However, the pineal organ of three salmonids (rainbow trout Oncorhynchus mykiss, masu salmon Oncorhynchus masou, and sockeye salmon Oncorhynchus nerka) did not exhibit cireadian rhythms in melatonin release when maintained under constant darkness (1313) in vitro, suggesting that the pineal organs of all salmonids lack the circadian regulation of melatonin production. To test this hypothesis, the pineal organ of seven salmonids (common whitefish Coregonus lavaretus, grayling Thymallus thymallus, Japanese huchen Hucho perryi, Japanese charr Salvelius leucomaenis pluvius, brook trout Salvelius fontinalis, brown trout Salmo trutta and chum salmon Oncorhynchus keta) and closely related osmerids (ayu Plecoglossus altivelis altivelis and Japanese smelt Hypomesus nipponensis) were individually maintained in flow-through culture at 15 degrees C under several light conditions. Under light-dark cycles, the pineal organ of all species showed a rhythmic melatonin release with high rates during the dark phase. Under DD, the osmerid pineal organs exhibited circadian rhythms in melatonin release with high rates only during the subjective-night but the salmonid pineal organs constantly released melatonin at high rates. Under constant light, melatonin release was suppressed in all species. The pineal organ of rainbow trout maintained at different temperature (15, 20 or 25 degrees C under DD released melatonin with high rates but the amount of melatonin released was temperature-sensitive (highest at 20 degrees C). Thus, melatonin release from the pineal organ of osmerids is regulated by both light and circadian clock but the circadian regulation is lacking in salmonids. These results indicate that ancestral salmonids lost the circadian regulation of melatonin production after the divergence from osmerid teleosts. (C) 2007 Elsevier Inc. All rights reserved.