Wegelius K, Pasternack M, Hiltunen J O, Rivera C, Kaila K, Saarma M, Reeben M
Institute of Biotechnology, and Biocentrum Helsinki, University of Helsinki, Finland.
Eur J Neurosci. 1998 Jan;10(1):350-7. doi: 10.1046/j.1460-9568.1998.00023.x.
The gamma-aminobutyric acid (GABA) receptor rho subunits recently cloned from rat and human retina are thought to form GABA receptor channels belonging to a pharmacologically distinct receptor class, termed GABA(C). In this work we have examined the distribution of rho1, rho2 and rho3 subunits, and found expression of all three transcripts in several regions of the rat nervous system. In situ hybridization revealed expression of rho2 in the adult rat retina and some other parts of the visual pathways. A high local rho2 expression was seen in the superficial grey layer of the superior colliculus, and in the dorsal lateral geniculate nucleus. Expression was also detected in the 6th layer of visual cortex and in the CA1 pyramidal cell layer of hippocampus. With reverse transcriptase-polymerase chain reaction, expression of rho1 was mainly seen in the adult rat retina and dorsal root ganglia, as well as, at a significantly lower level, in the superior colliculus, hippocampus, brain stem, thalamus, postnatal day 8 (P8) superior colliculus and P8 hippocampus. Expression pattern of rho3 mRNA was clearly different from that of rho1 and rho2, being strongest in the hippocampus, and significantly lower in the retina, dorsal root ganglia and cortex. No rho3 expression was observed in adult or P8 superior colliculus or in P8 hippocampus. The present results clearly demonstrate that expression of GABA receptor rho subunits is not restricted to the retina, but significant expression can also be detected in many other brain regions, especially in those belonging to the visual pathways. The expression pattern of the rho subunits may be helpful in solving the functional significance of the receptors formed from these subunits.
最近从大鼠和人类视网膜中克隆出的γ-氨基丁酸（GABA）受体rho亚基，被认为可形成属于药理学上独特受体类别的GABA受体通道，称为GABA(C)。在本研究中，我们检测了rho1、rho2和rho3亚基的分布，发现在大鼠神经系统的几个区域均有这三种转录本的表达。原位杂交显示rho2在成年大鼠视网膜及视觉通路的其他一些部位有表达。在上丘的浅灰层和背外侧膝状核中可见rho2的高局部表达。在视觉皮层第6层和海马CA1锥体细胞层也检测到了表达。通过逆转录-聚合酶链反应发现，rho1的表达主要见于成年大鼠视网膜和背根神经节，以及在上丘、海马、脑干、丘脑、出生后第8天（P8）的上丘和P8海马中以显著较低水平表达。rho3 mRNA的表达模式与rho1和rho2明显不同，在海马中最强，而在视网膜、背根神经节和皮层中显著较低。在成年或P8上丘或P8海马中未观察到rho3表达。目前的结果清楚地表明，GABA受体rho亚基的表达并不局限于视网膜，在许多其他脑区也能检测到显著表达，尤其是在那些属于视觉通路的脑区。rho亚基的表达模式可能有助于解决由这些亚基形成的受体的功能意义。
