Boue-Grabot E, Roudbaraki M, Bascles L, Tramu G, Bloch B, Garret M
Laboratoire de Neurophysiologie CNRS-UMR 5543, Université de Bourdeaux 2, France.
J Neurochem. 1998 Mar;70(3):899-907. doi: 10.1046/j.1471-4159.1998.70030899.x.
The GABA receptor rho1, rho2, and rho3 subunits are expressed in the retina where they form bicuculline-insensitive GABA(C) receptors. We used northern blot, in situ hybridization, and RT-PCR analysis to study the expression of rho subunits in rat brains. In situ hybridization allowed us to detect rho-subunit expression in the superficial gray layer of the superior colliculus and in the cerebellar Purkinje cells. RT-PCR experiments indicated that (a) in retina and in domains that may contain functional GABA(C) receptors, rho2 and rho1 subunits are expressed at similar levels; and (b) in domains and in tissues that are unlikely to contain GABA(C) receptors, rho2 mRNA is enriched relative to rho1 mRNA. These results suggest that both rho1 and rho2 subunits are necessary to form a functional GABA(C) receptor. The use of RT-PCR also showed that, except in the superior colliculus, rho3 is expressed along with rho1 and rho2 subunits. We also raised an antibody against a peptide sequence unique to the rho1 subunit. The use of this antibody on cerebellum revealed the rat rho1 subunit in the soma and dendrites of Purkinje neurons. The allocation of GABA(C) receptor subunits to identified neurons paves the way for future electrophysiological studies.
γ-氨基丁酸（GABA）受体rho1、rho2和rho3亚基在视网膜中表达，在那里它们形成对荷包牡丹碱不敏感的GABA(C)受体。我们使用Northern印迹、原位杂交和逆转录聚合酶链反应（RT-PCR）分析来研究rho亚基在大鼠脑中的表达。原位杂交使我们能够检测到上丘浅层灰质层和小脑浦肯野细胞中rho亚基的表达。RT-PCR实验表明：（a）在视网膜和可能含有功能性GABA(C)受体的区域，rho2和rho1亚基以相似的水平表达；（b）在不太可能含有GABA(C)受体的区域和组织中，相对于rho1 mRNA，rho2 mRNA富集。这些结果表明，rho1和rho2亚基都是形成功能性GABA(C)受体所必需的。RT-PCR的应用还表明，除了在上丘中，rho3与rho1和rho2亚基一起表达。我们还制备了一种针对rho1亚基独特肽序列的抗体。在小脑上使用这种抗体揭示了浦肯野神经元的胞体和树突中的大鼠rho1亚基。将GABA(C)受体亚基分配到已识别的神经元中为未来的电生理研究铺平了道路。
