Abnormalities of cAMP-dependent endogenous phosphorylation in platelets from patients with bipolar disorder

Objective: The aim of the study was to assess cAMP-dependent endogenous phosphorylation in platelets from euthymic bipolar patients. Methods: Platelets from 10 drug-free euthymic patients with bipolar disorder were compared with those from 10 age- and sex-matched healthy subjects. Basal and cAMP-stimulated protein phosphorylation was examined in each group. Results: Endogenous phosphorylation in both the healthy volunteers and the bipolar patients was significantly stimulated by cAMP; the major polypeptides had apparent molecular weights of 38 and 22 kDa. The cAMP-stimulated ³²P incorporation differed between the bipolar patients and the comparison subjects only in the 22-kDa band. Conclusions: These data suggest a possible role of cAMP-dependent protein phosphorylation in the pathophysiology of bipolar disorder.