Abnormal levels of cAMP-dependent protein kinase regulatory subunits in platelets from schizophrenic patients.

Abnormalities in the cAMP-dependent protein kinase (PKA), a central component of cAMP signaling, have been reported in several psychiatric disorders. Previous studies showed cAMP signaling alterations in schizophrenic patients but less is known about the involvement of PKA in such disorder. Therefore, we investigated the PKA subunits by Western blot analysis in platelets from 12 patients with schizophrenia and 13 controls. The results showed that the immunolabeling of the PKA regulatory subunits type I (RI) and type II (RII) was significantly reduced in patients compared with controls whereas no differences were observed in the catalytic (C) subunit of the enzyme. These preliminary data suggest that schizophrenic patients have altered PKA levels, thus supporting that dysfunctions in the components of cAMP signaling may contribute to the pathophysiology of schizophrenia.