Distribution of the gamma-aminobutyric acid(A) receptor complex alpha 5 subunit in chick brain. An immunocytochemical and autoradiographic study

This work reports the distribution of the gamma-aminobutyric acid(A) (GABA(A)) receptor complex alpha5 subunit in the chick using an antibody raised against this subunit in the rat, an immunoprecipitation study and a comparative autoradiographic study using [(3)H]flunitrazepam in the presence of 1 microM zolpidem, which is considered to bind only to those areas presenting the alpha5 subunit. The specificity of the antibody for the chick GABA(A) receptor complex alpha5 subunit is supported by the similar bands obtained by Western blotting from rat and chick, the immunoprecipitation study and the general agreement in the distribution and pattern of labelling of this antibody in both species. The immunocytochemical and autoradiographic distributions in both the chick and rat are compared and some areas with disagreement between these distributions are discussed. The general conclusion is that the alpha5 subunit of the GABA(A) complex receptor seems to have been conserved along evolution.