Single cell RT-PCR demonstrates differential expression of GABA C receptor ρ subunits in rat hippocampal pyramidal and granule cells

Abstract

Although γ-aminobutyric acid (GABA) C receptor ρ1, ρ2 and ρ3 subunits are reportedly expressed in pyramidal and granule cells in the hippocampus at various developmental stages, it is not clear whether these three ρ subunits are coexpressed in a single neuron. To attempt to answer this question, we performed single-cell RT-PCR for ρ subunits from neurons of rat brain hippocampus. In hippocampal cultures, pyramidal cells were positive for ρ1 mRNA expression in 89%, ρ2 in 94% and ρ3 in 94%, while granule cells were positive for ρ1 mRNA in only 6%, ρ2 in 36% and ρ3 in 91%. Intensive amplification of the RT-PCR products by the second PCR revealed that all the three ρ subunits were coexpressed in a single pyramidal and granule cells from both of the cultures and the slices. These results suggest that all the three GABA C receptor ρ1, ρ2 and ρ3 subunits are present probably in different compositions in pyramidal and granule cells in the rat hippocampus.