IDENTIFICATION OF GABA(A) RECEPTOR SUBUNITS IN RAT RETINA - CLONING OF THE RAT GABA(A) RECEPTOR RHO(2)-SUBUNIT CDNA

We identified GABA(A) receptor subunits in rat retina using PCR. The h igh degree of conservation among previously described members of ligan d-gated anion channels in transmembrane domains was used to design deg enerate sense and antisense oligonucleotides. These oligonucleotides w ere used as primers for PCR, which was applied to the rat retina cDNA. Analysis of clones derived from the PCR amplification identified the GABA(A) alpha(1), beta(1), beta(3), and gamma(2) subunits and the glyc ine alpha(1) subunit. In addition, two clones closely related to the h uman GABA(A) rho-subunit class were obtained. Molecular cloning reveal ed one of them as the rat counterpart of the human rho(2) subunit. Nor thern blot analysis demonstrated the expression of mRNAs for rho subun its in retina. These results further support the hypothesis that bicuc ulline-insensitive GABA channels in rat retina are comprised of rho su bunits.