PLATELET INTRACELLULAR CALCIUM IN PATIENTS WITH RECURRENT AFFECTIVE-DISORDERS

Forty-four subjects with a history of a major recurrent affective diso rder in remission and who were either on no medication or taking a sin gle dose of psychotropic medication were conscripted together with mat ched controls. The fluorescent indicator fura 2 was used to measure in tracellular calcium in platelets and estimations were made of total se rum and ionised calcium as well as of whole blood serotonin. Intracell ular calcium was measured in the resting state as well as after stimul ation with thrombin, platelet activating factor and serotonin. No sign ificant differences were found between the 17 subjects with a diagnosi s of bipolar disorder or the 27 subjects with recurrent unipolar depre ssion and their matched controls. Intracellular calcium measures were significantly higher in the lithium treated group after stimulation wi th 5HT, whereas the subjects taking tricyclic antidepressants did not differ significantly from their controls on any measure. Serum calcium was found to be significantly higher in those subjects taking lithium . These findings suggest that the measurement of intracellular calcium is not a useful trait marker in affective disorders. Lithium appears to enhance the 5HT induced rise of intracellular calcium.