STIMULATORY G-PROTEIN ALPHA-SUBUNIT MESSENGER-RNA LEVELS ARE NOT INCREASED IN AUTOPSIED CEREBRAL-CORTEX FROM PATIENTS WITH BIPOLAR DISORDER

Increased alpha-subunit (alpha(s)) levels of both the 45- and 52-kDa i soforms of the stimulatory guanine nucleotide binding protein (G-prote in), have been found in postmortem brain and mononuclear leukocytes fr om patients with bipolar disorder (BD), The pathophysiological mechani sm responsible for increased alpha(s) protein levels is unknown, howev er, it may involve increased expression of the gene encoding this prot ein. To assess this possibility, alpha(s) mRNA levels were determined by RT-PCR in postmortem brain from 10 subjects with an antemortem diag nosis of ED and age- and sex-matched control subjects in whom we had p reviously reported increased alpha(s) protein levels. There were no si gnificant differences in alpha(s) mRNA levels in frontal, temporal, or occipital cortex between ED and control subjects. Cerebral cortex alp ha(s) mRNA levels did not correlate with age or postmortem interval. T hese findings do not support the notion that higher alpha(s) levels fo und in ED postmortem brain are a result of increased gene expression.