Circadian rhythm of AMPA receptor GluR2/3 subunit-immunoreactivity in the suprachiasmatic nuclei of Syrian hamster and effect of a light-dark cycle
Circadian rhythm of AMPA receptor GluR2/3 subunit-immunoreactivity in the suprachiasmatic nuclei of Syrian hamster and effect of a light-dark cycle
复制标题
DOI：
10.1016/s0006-8993(99)01460-2
复制
发表时间：
1999-06-26
期刊：
影响因子：
2.9
通讯作者：
Chambille, I
中科院分区：
文献类型：
--
作者：
Chambille, I
在哺乳动物中，下丘脑的视交叉上核（SCN）是产生和协调许多内源性生理和行为节律的昼夜节律钟的场所。SCN通常通过使用谷氨酸作为神经递质的直接视网膜传入被带入光/暗（LD）循环。N-甲基-D-天冬氨酸（NMDA）和非NMDA受体参与SCN的光夹带。在啮齿类动物中，四种已知的2-氨基-3-（3-羟基-（4-甲基异恶唑-4-基）丙酸（AMPA）受体亚基中的三种已被原位杂交证实。本研究分析了在恒定黑暗（DD）和12：12 LD周期下维持的叙利亚仓鼠SCN中GluR 2/3亚基的表达。在动物提交DD或LD，小的免疫反应神经元位于腹侧和外部侧腹侧的部分的嘴侧三分之二的SCN和沿着对称平面。在DD中维持的三组动物中的六个昼夜节律时间（CT）和在LD中提交的一组仓鼠中的六个昼夜节律时间（zeitgeber time，ZT）时间，对具有或不具有长突起的强标记神经元的数量进行计数。在DD，我们观察到显着更多的GluR 2/3亚单位免疫反应（GluR 2/3-ir）神经元在主观的白天比在主观的夜晚，在CT 19-CT 2/3的最小值。LD周期显著减少免疫反应神经元的数量，减少LD时相之间的差异，并在光转换时抑制免疫反应，即，在ZT 11和ZT 23。本研究首次通过免疫组化证明了啮齿动物SCN中AMPA受体亚基表达的昼夜动态的存在以及LD周期对这种动态的影响。(C)1999 Elsevier Science B. V.保留所有权利。
In mammals, the suprachiasmatic nuclei (SCN) of the hypothalamus are the site of the circadian clock that generates and coordinates many endogenous physiological and behavioral rhythms. SCN are normally entrained to light/dark (LD) cycle by direct retinal afferents using glutamate as neurotransmitter. N-Methyl-D-aspartate (NMDA) and non-NMDA receptors are involved in photic entrainment of SCN. In rodents, the presence of three of the four known 2-amino-3-(3-hydroxy-(-methylisoaxol-4-yl) propanoic acid (AMPA) receptor subunits has been demonstrated by in situ hybridization. This study analyzes the expression of GluR2/3 subunits in SCN of Syrian hamsters maintained under constant darkness (DD) or 12:12 LD cycle. In animals submitted to DD or LD, small immunoreactive neurons were located in the ventral and external latero-ventral parts of the rostral two-thirds of the SCN and along the symmetrical plane. The number of intensely labeled neurons with or without long process(es) were counted at six circadian times (CTs) in three groups of animals maintained in DD and six nycthemeral (zeitgeber time, ZT) times in one group of hamsters submitted to LD. In DD, we observed significantly more GluR2/3 subunit-immunoreactive (GluR2/3-ir) neurons during the subjective day than during the subjective night, with minima at CT 19-CT 23. The LD cycle significantly reduced the number of immunoreactive neurons, lessened the differences between LD phases and depressed immunoreactivity at light transition, i.e., at ZT 11 and ZT 23. This study demonstrates for the first time by immunohistochemistry the existence of a circadian dynamic of the expression of AMPA receptor subunits in SCN of rodents and the effect of the LD cycle on this dynamic. (C) 1999 Elsevier Science B.V. All rights reserved.