Expression and localization of the neuronal glycine receptor beta-subunit in human, rabbit and rat kidneys

The glycine receptor (GlyR) is a ligand-gated Cl- channel composed of two t ransmembrane subunits, alpha and beta, and gephyrin. The goal of this study was to determine whether the alpha- and/or beta-subunits of the GlyR are e xpressed in human, rabbit and/or rat kidneys. Screening of human and rat ki dney cortex cDNA libraries identified polymerase chain reaction products th at were identical to the neuronal GlyR beta-subunit. Sequencing revealed th at rat kidney cortex and neuronal GlyR beta-subunits were identical. RNA is olated from the S-2 segment of rabbit renal proximal tubules (RPT) and rat and rabbit kidney cortex was amplified following reverse transcription and gave similar results to that of human and rat kidney cDNA libraries. Degene rate primers against all GlyR alpha-subunits did not yield a product from r at and rabbit kidney cortex RNA, or from human and rat kidney cortex cDNA l ibraries. Immunofluorescence studies localized the beta-subunit and gephyri n to the basolateral membrane of rabbit RPT. These results provide compelli ng evidence for the GlyR beta-subunit, but not the alpha-subunit, in human, rabbit and rat kidney cortex.