The roles of circadian clocks in the regulation of digestive system in fish

1.消化酶活性的日变化为了研究消化酶活性是否存在日变化，在光暗周期和恒定黑暗条件下对虹鳟鱼消化道进行了解剖。α-淀粉酶和脂肪酶活性的测定正在进行中。2.褪黑激素在消化道中的作用褪黑激素是脊椎动物体内的一种Zeitgeber。为了测试褪黑激素是否在鱼的消化道中产生，测定了褪黑激素含量。结果，在虹鳟鱼消化道的所有区域都检测到褪黑激素。但是，没有每日变化。分子生物学研究表明，鱼类消化道中不存在AANAT mRNA，说明褪黑激素不是在消化道原位产生的.利用Fos免疫组化技术对鱼脑内摄食性昼夜节律振荡器进行了定位研究。然而，未获得阳性信号。

1.Daily variations in enzyme activities involved in digestionTo investigate whether activities of digestive enzymes exhibit daily variations, digestive tracts of the rainbow trout were dissected under light-dark cycles and constant darkness. Determination of alpha amylase arid lipase activities is now in progress.2.Roles of melatonin in digestive tractsMelatonin is an internal Zeitgeber in vertebrates. To test whether melatonin is produced in the digestive tracts of fish, melatonin contents were determined. As a results, melatonin was detected in all regions of the digestive tracts of the rainbow trout. However, there was no daily variations. Molecular biological studies have demonstrated that there was no AANAT mRNA in fish digestive tract, indicating that melatonin is not produced in the digestive tract in situ.3. Localization of feeding-entrainable circadian oscillatorcFos immunohistbchemistry was used to identify of feeding-entrainable circadian oscillator in fish brain. However, no positive signal was obtained.