An mRNA Encoding a Putative GABA-Gated Chloride Channel Is Expressed in the Human Cardiac Conduction System
Journal of Neurochemistry. 2002-11-18; 68(4): 1382-1389
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1. J Neurochem. 1997 Apr;68(4):1382-9.
An mRNA encoding a putative GABA-gated chloride channel is expressed in the human
cardiac conduction system.
Garret M(1), Bascles L, Boue-Grabot E, Sartor P, Charron G, Bloch B, Margolskee
(1)Laboratoire de Neurophysiologie, Université de Bordeaux 2, France.
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.
PMID: 9084408 [Indexed for MEDLINE]