Garret M, Bascles L, Boue-Grabot E, Sartor P, Charron G, Bloch B, Margolskee R F
Laboratoire de Neurophysiologie, Université de Bordeaux 2, France.
J Neurochem. 1997 Apr;68(4):1382-9. doi: 10.1046/j.1471-4159.1997.68041382.x.
GABA-gated chloride channels are the main inhibitory neurotransmitter receptors in the CNS. Conserved domains among members of previously described GABAA receptor subunits were used to design degenerate sense and antisense oligonucleotides. A PCR product from this amplification was used to isolate a full-length cDNA. The predicted protein has many of the features shared by other members of the ligand-gated ion channel family. This channel subunit has significant amino acid identity (25-40%) with members of GABAA and GABAC receptor subunits and thus may represent a new subfamily of the GABA receptor channel. Although we cannot rule out that this clone encodes a receptor for an unidentified ligand, it was termed GABA chi. This gene is mainly expressed in placenta and in heart; however, placenta appears to express only an unspliced mRNA. In situ hybridization reveals that the GABA chi subunit mRNA is present in the electrical conduction system of the human heart. Our results suggest that novel GABA receptors expressed outside of the CNS may regulate cardiac function.
γ-氨基丁酸（GABA）门控氯离子通道是中枢神经系统（CNS）中主要的抑制性神经递质受体。利用先前描述的GABAA受体亚基成员之间的保守结构域设计简并正义和反义寡核苷酸。该扩增产物的PCR产物用于分离全长cDNA。预测的蛋白质具有配体门控离子通道家族其他成员共有的许多特征。该通道亚基与GABAA和GABAC受体亚基成员具有显著的氨基酸同一性（25-40%），因此可能代表GABA受体通道的一个新亚家族。尽管我们不能排除该克隆编码一种未知配体的受体，但它被命名为GABA chi。该基因主要在胎盘和心脏中表达；然而，胎盘似乎只表达未剪接的mRNA。原位杂交显示，GABA chi亚基mRNA存在于人类心脏的传导系统中。我们的结果表明，在中枢神经系统之外表达的新型GABA受体可能调节心脏功能。
