Recombinant GABA_C receptors expressed in rat hippocampal neurons after infection with an adenovirus containing the human ρ1 subunit

1. A recombinant adenovirus was generated with the human ρ1 GABA_C receptor subunit (adeno-ρ). Patch-clamp and antibody staining were employed to confirm functional expression of recombinant ρ1 receptors after infection of human embryonic kidney cells (HEK293 cell line), human embryonic retinal cells (911 cell line), dissociated rat hippocampal neurons and cultured rat hippocampal slices. 2. Standard whole-cell recording and Western blot analysis using ρ1 GABA_C receptor antibodies revealed that recombinant ρ1 receptors were expressed in HEK293 and 911 cells after adeno-ρ infection and exhibited properties similar to those of ρ1 receptors after standard transfection. 3. Cultured rat hippocampal neurons (postnatal day (P)3-P5) did not show a native GABA_C-like current. After adeno-ρ infection, however, a GABA_C-like current appeared in 70-90% of the neurons. 4. Five days after infection, expression of GABA_C receptors in hippocampal neurons significantly decreased native GABA_A receptor currents from 1200 ± 300 to 150 ± 70 pA (n = 10). The native glutamate-activated current was unchanged. 5. Hippocampal slices (P8) did not show a native GABA_C-like current, although recombinant ρ1 receptors could be expressed in cultured hippocampal slices after adeno-ρ infection. 6. These data indicate that an adenovirus can be used to express recombinant GABA_C receptors in hippocampal neurons. This finding could represent an important step towards the gene therapy of CNS receptor-related diseases.