Abstract
Although the properties and functions of GABAA receptors in the mammalian central nervous system have been well studied, the presence and significance of GABAA receptors in non-neural tissues are less clear. The goal of this study was to examine the expression of GABAA receptor α1, α2, α4, α5, β1, γ1, γ2, and δ subunits in the kidney and to determine whether these subunits coassemble to form an active renal epithelial cell GABAA receptor. Using reverse transcriptase products from RNA isolated from rat and rabbit kidney cortex and brain or cerebellum through polymerase chain reaction (PCR) and sequencing of the PCR products, we revealed that rat kidney cortex contained the α1, α5, β1, γ1, and γ2 subunits and that they were similar to the neuronal subunits. Sequencing of the PCR products revealed that the rabbit kidney cortex contained the α1 and γ2 subunits and that they were similar to their neuronal counterparts. Immunoprecipitation and immunoblot studies using GABAA receptor subunit-specific antibodies and detergent-solubilized rat kidney cortex membranes identified a GABAA receptor complex containing α5, β1, and γ1. Isolated rat renal proximal tubular cells exhibited GABA-mediated, picrotoxin-sensitive 36Cl- uptake. These studies demonstrate the presence of numerous GABAA receptor subunits in the kidneys of two species, the assembly of the subunits into at least one novel receptor complex, and an active GABAA receptor in renal proximal tubular cells.
Footnotes
-
B.S.C. was supported by an individual National Research Service Award from the National Institutes of Health (DK-10079). Dr. S. S. Sarang was supported by an American Heart Association Arkansas Affiliate Predoctoral Fellowship. Dr. R. G. Schnellmann was supported by the National Institute of Diabetes and Digestive and Kidney Diseases (DK-52946).
-
Article, publication date, and citation information can be found at http://jpet.aspetjournals.org.
-
doi:10.1124/jpet.107.129957.
-
ABBREVIATIONS: CNS, central nervous system; RT, reverse transcriptase; PCR, polymerase chain reaction; RPT, renal proximal tubule; bp, base pair.
-
↵1 Current affiliation: Alcon Laboratories, Fort Worth, Texas.
-
↵2 Current affiliation: Department of Pharmaceutical and Biomedical Sciences, University of Georgia, Athens, Georgia.
- Received August 17, 2007.
- Accepted October 22, 2007.
- The American Society for Pharmacology and Experimental Therapeutics
JPET articles become freely available 12 months after publication, and remain freely available for 5 years.Non-open access articles that fall outside this five year window are available only to institutional subscribers and current ASPET members, or through the article purchase feature at the bottom of the page.
|