Huhman K L, Hennessey A C, Albers H E
Department of Biology, Georgia State University, Atlanta 30303, USA.
J Biol Rhythms. 1996 Dec;11(4):311-6. doi: 10.1177/074873049601100404.
The purpose of the present study was to determine whether there is a rhythm in glutamic acid decarboxylase (GAD) message in the suprachiasmatic nucleus (SCN) of rats housed in a light:dark cycle. The mRNAs encoding two isoforms of GAD (i.e., GAD65 and GAD67) were examined using in situ hybridization histochemistry. Computerized image analysis of film autoradiographs revealed that GAD65 mRNA was significantly higher in the light than it was in the dark. GAD67 mRNA levels were lower overall and did not decrease significantly in the dark. Following emulsion autoradiography, silver grain counts over individual SCN cells indicated that GAD65 mRNA was highest in the dorsomedial hypothalamus during the light. These data suggest that GAD mRNA varies rhythmically in the SCN and that mRNA levels are regulated differently within SCN subdivisions during the light:dark cycle.
本研究的目的是确定处于明暗周期中的大鼠视交叉上核（SCN）内谷氨酸脱羧酶（GAD）信息是否存在节律。使用原位杂交组织化学检测编码GAD两种同工型（即GAD65和GAD67）的mRNA。对胶片放射自显影片进行计算机图像分析显示，GAD65 mRNA在光照下显著高于黑暗中。GAD67 mRNA水平总体较低，在黑暗中没有显著下降。进行乳胶放射自显影后，对单个SCN细胞上的银颗粒计数表明，光照期间背内侧下丘脑的GAD65 mRNA最高。这些数据表明，GAD mRNA在SCN中呈节律性变化，并且在明暗周期中SCN各亚区内mRNA水平受到不同调节。
