Increased platelet intracellular calcium concentration in patients with bipolar affective disorders
S. L. Dubovsky, J. Christiano, L. C. Daniell, R. D. Franks, J. Murphy, L. Adler, N. Baker and R. A. Harris
Department of Psychiatry, University of Colorado School of Medicine, Denver.
Using the fluorescent indicator Fura 2, we measured the free intracellular
calcium ion concentration in blood platelets of patients with untreated
mania, bipolar depression, and unipolar depression; patients who had
recovered from bipolar depression or mania; and age- and sex-matched
controls. The baseline intracellular calcium ion concentration was
significantly increased in platelets from patients with mania compared with
controls. The free intracellular calcium ion concentration after
stimulation with platelet-activating factor and thrombin was significantly
higher in platelets of manic and bipolar depressed patients than in all
other groups. The degree to which intracellular calcium ion concentration
increased over baseline after stimulation was significantly lower in
unipolar than in bipolar patients. These findings suggest that platelets of
manic and depressed bipolar patients have a similar enhancement of
intracellular calcium ion activity that is distinctly different from the
decreased ability of platelets of unipolar patients to mobilize
intracellular calcium in response to stimulation.
