Immunohistochemical and immunoblot study of GABAA α1 and β2/3 subunits in the prefrontal cortex of subjects with schizophrenia and bipolar disorder

A number of investigations have provided a growing body of evidence of the involvement of the gamma-aminobutyric acid (GABA) transmitter system in the pathophysiology of schizophrenia and bipolar disorder. In this study, immunohistochemical and immunoblot techniques were employed in order to examine alterations of the GABA(A) receptor alpha1 and beta2/3 subunits in the prefrontal cortex from postmortem subjects with schizophrenia and bipolar disorder. alpha1 immunoreactivity was observed in the neuropil of the prefrontal cortex and in the neuronal soma in specimens from both groups, as well as from normal controls. alpha1 immunolabeling, in the neuronal soma from the schizophrenic group was more intense than that of the other two groups. The distribution of beta2/3 immunoreactivity was similar to that of alpha1. beta2/3 immunolabeling in the neuronal soma from the schizophrenia and bipolar disorder groups was more intense than that of the normal controls. The densitometry measurements. as well as the immunoblot analysis for alpha1 and beta2/3 were highly consistent with the alpha1 and beta2/3 immunohistochemistry results. The present study suggests that the expression of these two GABA(A) receptor subunits was altered in subjects with schizophrenia and bipolar disorder, but that the patterns of change differed between those with these two disorders. (C) 2004 Elsevier Ireland Ltd and The Japan Neuroscience Society. All rights reserved.