Cagampang F R, Rattray M, Powell J F, Campbell I C, Coen C W
Division of Biomedical Sciences, King's College, London, UK.
Neuroreport. 1996 Aug 12;7(12):1925-8. doi: 10.1097/00001756-199608120-00011.
Gaba has been implicated in the regulation of the circadian clock within the suprachiasmatic nuclei (SCN). In the present study in situ hybridization histochemistry was used to assess expression of mRNA for the two isoforms of the enzyme governing GABA synthesis, glutamic acid decarboxylase (GAD) 65 and 67, within the rat SCN during a 24 h cycle in constant darkness. GAD 65 mRNA exhibited a monophasic rhythm, with a peak at the beginning of the subjective day and a nadir early in the subjective night. In contrast, there was a biphasic variation in GAD 67 expression, with peaks at the beginning of the subjective day and early in the subjective night. No significant variation in the mRNAs for GAD 65 or GAD 67 was observed in the cingulate cortex. These results suggest that the clock intrinsic to the SCN controls the expression of the mRNAs encoding GAD 65 and GAD 67 in both a coordinated and a differential manner.
γ-氨基丁酸（Gaba）已被证实参与视交叉上核（SCN）内昼夜节律时钟的调节。在本研究中，采用原位杂交组织化学技术，在持续黑暗环境下的24小时周期内，评估大鼠SCN中控制Gaba合成的两种同工酶——谷氨酸脱羧酶（GAD）65和67的mRNA表达情况。GAD 65 mRNA呈现单峰节律，在主观日开始时达到峰值，在主观夜早期降至最低点。相比之下，GAD 67的表达存在双相变化，在主观日开始时和主观夜早期出现峰值。在扣带回皮质中未观察到GAD 65或GAD 67的mRNA有显著变化。这些结果表明，SCN固有的生物钟以协调和差异的方式控制着编码GAD 65和GAD 67的mRNA的表达。
