Light-Dark and Circadian Melatonin Rhythms Are Established de novo in Re-Aggregates of the Embryonic Chicken Retina
Light-Dark and Circadian Melatonin Rhythms Are Established de novo in Re-Aggregates of the Embryonic Chicken Retina
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明暗和昼夜节律褪黑素节律在鸡胚视网膜的重新聚集中重新建立
DOI：
10.1159/000069361
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发表时间：
2003
影响因子：
2.9
通讯作者：
P. Layer
中科院分区：
文献类型：
--
作者：
E. Willbold;J. Huhn;H. Korf;P. Voisin;P. Layer
鸡光感受器的一个核心功能是神经激素褪黑激素的节律性合成;然而，尚不清楚它们如何在孵化前（即没有光照）实现昼夜节律起搏器系统。在这里，我们研究了褪黑激素的合成和分泌的玫瑰花球状体，这是从头组织型球体，重新聚集从解离的视网膜细胞的鸡胚。在12小时光照/12小时黑暗循环期间培养球状体。在培养的第5天附近的球状体中的感光细胞分化开始后不久，褪黑激素分泌开始，并且在培养的第8天，显示出明显的暗光振荡，在黑暗期间具有高值，在光照期间具有较低的值。同时，褪黑激素合成的两个关键酶，芳基烷基胺-N-乙酰转移酶（AA-NAT）和羟基吲哚-O-甲基转移酶（HIOMT）的表达检测北方印迹分析从第6天开始，增加，直到第8天。只有HIOMT，而不是AA-NAT水平是2- 3倍高，在结束时的光相比，黑暗阶段。即使在永久黑暗下，6天后也显示轻微的褪黑激素振荡。总之，从头再生的视网膜球状体中的光感受器变得对光敏感，建立适当的褪黑激素合成途径，并在黑暗中分泌更多的褪黑激素。潜在的昼夜节律起搏器似乎取决于感光细胞的分化，而不是以前的光暗夹带。
A central function of chicken photoreceptors is the rhythmic synthesis of the neurohormone melatonin; however, it is unclear how they can achieve – already before hatching (i.e. without light exposure) – a circadian pacemaker system. Here we studied melatonin synthesis and secretion in rosetted spheroids, which are de novo histotypic spheres, re-aggregated from dissociated retinal cells of chicken embryos. Spheroids were cultured during a 12-hour light/12-hour dark cycle. Shortly after the onset of photoreceptor differentiation in spheroids near day 5 in culture, melatonin secretion set in and, by day 8 in culture, showed distinct dark-light oscillations, with high values during the dark and lower ones during the light period. Concomitantly, expression of two key enzymes of melatonin synthesis, arylalkylamine-N-acetyltransferase (AA-NAT) and hydroxyindole-O-methyltransferase (HIOMT) was detected by northern blot analysis from day 6 onwards, increasing until day 8. Only HIOMT, but not AA-NAT levels were 2- to 3-fold higher at the end of the light compared with the dark phase. Even under permanent darkness, a slight melatonin oscillation was revealed after 6 days. In conclusion, photoreceptors in de novo regenerated retinal spheroids become light-responsive, establish appropriate pathways for melatonin synthesis and secrete more melatonin in the dark. The underlying circadian pacemaker seems to depend on photoreceptor differentiation, not on previous light-dark entrainment.
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鸡视网膜中褪黑激素的生物合成。
影响因子：
--
作者：
Iuvone,PM;Chong,NW;Bernard,M;Brown,AD;Thomas,KB;Klein,DC
通讯作者：
Klein,DC
影响因子：
3.4
作者：
MOSINGER, JL;YAZULLA, S;STUDHOLME, KM
通讯作者：
STUDHOLME, KM
脊椎动物视网膜中的 HIOMT 样免疫反应性：物种比较。
影响因子：
3.4
作者：
Wiechmann,AF;Hollyfield,JG
通讯作者：
Hollyfield,JG
视网膜前体细胞的可塑性和分化。
DOI：
10.1016/s0074-7696(08)60382-4
发表时间：
1993
期刊：
International review of cytology
影响因子：
--
作者：
Adler,R
通讯作者：
Adler,R