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MECHANISM OF CIRCADIAN OSCILLATION IN PHOTORECEPTIVE PINEAL ORGAN.

光感受松果体的昼夜节律振荡机制。

基本信息

批准号：
07839002
负责人：
SAMEJIMA Michikazu
金额：
$ 0.83万
依托单位：
HAMAMATSU UNIVERSITY SCHOOL OF MEDICINE
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1997
项目状态：
已结题

项目摘要

THE AIM OF THIS RESEARCH IS TO CLARIFY THE ROLE OF PINEAL ORGAN IN LOWER VERTEBRATE AND RELATE IT TO THE REGULATOYR FUNCTION OF THE ORGANISM IN THE PHYLOGENTIC POINT OF VIEW.FOR THIS PURPOSE,AUTHORS DID THE FOLLOWING EXPERIMENTS.IN 1995, WE TRIED TO FIND OUT THE ENDOGENOUS OASILLATOR IN THE PINEAL ORGAN OF LOWER VERTEBRATE SUCH AS LAMPREY.AS A RESULT,WE SUCCESSFULLY DETECTED THE ENDOGENOUS OASILLATOR IN THE ISOLATED AND CULTURED PINEAL ORGAN OF LAMPREY BY MEASURING MELATONIN SECRETION RHYTHM IN THE CULTURE MEDIUM UNDER CONTINUOUS DARK CONDITION AS WELL AS UNDER LIGHT-DARK CONDITION.IN 1996, TEMPERATURE DEPENDENCE WAS OBSERVED IN THE MELATONIN SECRETION RHYTHM FROM THE ISOLATED AND CULTURED PINEAL ORGAN.MELATONIN SECRETION WAS SUPPRESSED COMPLETELY AT 10ﾟC.THIS WAS INTERPRETED THAT OSCILLTOR ITSELF DOES NOT STOP AT 10ﾟC BUT THE SOME PROCESS IN MELATONIN BIOSYNTHESIS IS HIGHLY TEMPERATURE DEPENDENT AND IT IS SUPRESSED AT 10ﾟC.IN 1996 AND 1997, THE EFFECT OF LIGHT SCHEDULE ON MELATONIN SECRETION WAS INVESTIGATED.WHEN LIGHT-DARK (LD) CYCLES WERE SHIFTED FORWARD OR BACKWARD,MELATONIN RHYHTM WAS ALSO SHIFTED FORWARD OR BACKWORD AND RE-ENTRAINED TO THE NEW LD CYCLE IMMEDIATELY.WHEN THE PINEAL ORGAN WAS KEPT UNDER CONTINUOUS LIGHT CONDITION,MELATONIN SECRETION RHYTHM WAS DUMPED AND DISAPPEARED WITHIN 3 TO 4 DAYS.THESE RESULTS INDICATE THAT THE ISOLATED PINEAL ORGAN IS STILL PHOTOSENSITIVE UNDER CULTURE CONDITION.IT SEEMS TO BE QUITE IMPORTANT TO CONTINUE THE EXPERIMENTS TO KNOW THE CELLULAR MECHANISM OF PHOTORESPONSE OF THE PINEAL OSCILLATOR.

本研究的目的是从系统发生学的角度阐明松果体在低等脊椎动物中的作用，并阐明松果体对生物体的调节功能。为此，作者进行了以下实验：1995年，我们试图在低等脊椎动物如Lamprey的松果体中找到内源性振荡器。结果表明，通过测定连续黑暗条件和光暗条件下培养液中褪黑激素的分泌节律，我们成功地检测到了分离培养的灯笼草松果体中的内源性调节子。从分离培养的松果体中观察到褪黑激素分泌节律的温度依赖性。褪黑激素的分泌在10 ℃时被完全抑制。这解释了振荡器本身在10 ℃时并不停止，但褪黑激素生物合成中的某些过程高度依赖于温度，并在10 ℃时被抑制。1996年，1997年，我们研究了光照对褪黑素分泌的影响。当光暗周期向前或向后移动时，褪黑素节律也向前或向后移动，并立即重新进入新的光暗周期。当松果体处于连续光照条件下时，褪黑素分泌节律在培养3 ~ 4天后消失，表明松果体在培养条件下仍具有光敏性，继续实验以了解松果体振荡器光反应的细胞机制是十分重要的。