Iigo Masayuki, Ikeda Emi, Sato Masaru, Kawasaki Shigekatsu, Noguchi Fumitaka, Nishi Genjirou
Department of Applied Biochemistry, Faculty of Agriculture, Utsunomiya University, 350 Mine-machi, Utsunomiya, Tochigi 321-8505, Japan.
Gen Comp Endocrinol. 2006 Jan 1;145(1):32-8. doi: 10.1016/j.ygcen.2005.06.010. Epub 2005 Aug 22.
Using in vivo and in vitro methods we studied the regulation of ocular melatonin rhythms in the wrasse Halichoeres tenuispinnis, by either light or the circadian clock. Rhythmic changes in ocular melatonin levels under light-dark (LD) cycles were persistent under constant darkness (DD), and had a circadian periodicity of approximately 24h. However, ocular melatonin levels remained low under constant light conditions. When wrasse were exposed to a single 6-h light pulse at three different circadian phases under DD, phase-dependent phase shifts in the circadian rhythms of ocular melatonin were observed. When eyecups were prepared during mid-light periods or at the onset of darkness, and incubated in vitro in either light or dark periods, both time and light conditions affected melatonin release. These results indicate that the melatonin rhythms in the wrasse eye are driven by an ocular circadian clock that is entrained to LD cycles via local photoreceptors.
我们使用体内和体外方法，研究了光或昼夜节律钟对细棘海猪鱼（Halichoeres tenuispinnis）眼部褪黑素节律的调节。在明暗（LD）循环下，眼部褪黑素水平的节律性变化在持续黑暗（DD）条件下仍然持续存在，并且具有约24小时的昼夜周期。然而，在持续光照条件下，眼部褪黑素水平仍然较低。当细棘海猪鱼在DD条件下的三个不同昼夜阶段暴露于单个6小时光脉冲时，观察到眼部褪黑素昼夜节律的相位依赖性相移。当在光照中期或黑暗开始时制备眼杯，并在光照或黑暗时期进行体外培养时，时间和光照条件都会影响褪黑素的释放。这些结果表明，细棘海猪鱼眼睛中的褪黑素节律是由眼部昼夜节律钟驱动的，该时钟通过局部光感受器与LD循环同步。
