cAMP-Dependent protein kinase (PKA) subunit mRNA levels in postmortem brain from patients with bipolar affective...

Earlier findings of elevated basal and stimulated PKA activities, and increased immunoreactive levels of PKA regulatory and catalytic subunits in discrete postmortem brain regions from bipolar disorder (BD) patients suggest that disturbances in PKA are involved in the pathophysiology of BD. PKA subunit mRNA levels were measured using SYBR Green real-time RT-PCR to determine if previously observed differences in immunoreactive levels of PKA RIIbeta and Calpha subunits were associated with corresponding changes in mRNA levels in temporal and frontal cortices from the same BD patients and matched controls. In distinct contrast to the higher immunolabeling levels of the PKA subunits previously reported in the BD brain, there were no significant differences in RIIbeta and Calpha subunit mRNA levels in the temporal and frontal cortices of BD patients compared with controls. These findings infer that the elevated PKA immunolabeling and activity found in the selected cerebral cortical regions of BD postmortem brain were due to a posttranscriptional mechanism, rather than changes in regulation of gene transcription and/or mRNA stability of the PKA subunits.