The cAMP-dependent protein kinase substrate Rap1 in platelets from patients with obsessive compulsive disorder or schizophrenia

Previous studies have reported that the cAMP-dependent protein kinase and one of its substrates, namely Rap1, are altered in patients with affective disorders. Abnormalities in the cAMP-dependent protein kinase have also been reported in platelets of patients with obsessive compulsive disorder and schizophrenia. However, it remains to be determined whether abnormalities in Rap1 are specifically related to affective disorders or may also be present in schizophrenia and obsessive compulsive disorder. Thus, we investigated Rap1 in platelets from 12 drug-free patients with obsessive compulsive disorder, ten drug-free patients with schizophrenia, and 20 healthy subjects. While no difference was observed in the levels of Rap1 between groups, the phosphorylation state of Rap1 was significantly lower in patients with obsessive compulsive disorder than in schizophrenic patients and controls. These data further support the idea that abnormalities of cAMP signalling pathway could be associated, albeit in a somewhat different way, with several psychiatric disorders.