Huntsman M M, Leggio M G, Jones E G
Department of Anatomy and Neurobiology, University of California, Irvine 92717, USA.
J Comp Neurol. 1995 Feb 6;352(2):235-47. doi: 10.1002/cne.903520207.
The expression and regulation of seven GABAA receptor subunit gene transcripts were examined in the adult monkey lateral geniculate nucleus. In situ hybridization histochemistry was used to localize mRNAs of the genes encoding monkey-specific alpha 1, alpha 2, alpha 4, alpha 5, beta 1, beta 2, and gamma 2 subunits. The highest levels of expression in the nucleus were for alpha 1, beta 2, and gamma 2 subunit transcripts. The levels were substantially higher in the magnocellular than in the parvocellular layers. Alpha-2, alpha 4, alpha 5, and beta 1 subunit mRNAs were expressed at much lower levels, and magno- and parvocellular layers had approximately equal levels of expression. Following 4- or 21-day periods of monocular deprivation induced by intravitreal injections of tetrodotoxin, levels of the alpha 1, alpha 2, alpha 4, alpha 5, beta 1, and beta 2 mRNAs were decreased in the deprived geniculate laminae. Adjacent sections hybridized with probes specific for 67-kDa glutamic acid decarboxylase (GAD) mRNA also showed decreased levels of expression in deprived laminae after the 21-day deprivation period. Levels of gamma 2 receptor subunit mRNA were unaffected by monocular deprivation. In our previous studies, a clearly significant downregulation is observed for this subunit transcript in the visual cortex of monkeys deprived for equivalent times. The differential expression and responses to deprivation in the lateral geniculate nucleus suggest region-specific regulation of GABAA receptor subunit genes.
在成年猴外侧膝状核中检测了七种GABAA受体亚基基因转录本的表达及调控情况。采用原位杂交组织化学方法定位编码猴特异性α1、α2、α4、α5、β1、β2和γ2亚基的基因的mRNA。该核中表达水平最高的是α1、β2和γ2亚基转录本。其水平在大细胞层显著高于小细胞层。α2、α4、α5和β1亚基mRNA的表达水平要低得多，且大细胞层和小细胞层的表达水平大致相等。在玻璃体内注射河豚毒素诱导单眼剥夺4天或21天后，剥夺侧膝状核层中α1、α2、α4、α5、β1和β2 mRNA的水平降低。用针对67-kDa谷氨酸脱羧酶（GAD）mRNA的特异性探针杂交的相邻切片在21天剥夺期后也显示剥夺层中的表达水平降低。γ2受体亚基mRNA的水平不受单眼剥夺的影响。在我们之前的研究中，在同等时间剥夺的猴视觉皮层中观察到该亚基转录本有明显的下调。外侧膝状核中不同的表达及对剥夺的反应提示GABAA受体亚基基因存在区域特异性调控。
