Platelet glutamate receptor supersensitivity in major depressive disorder

Dysregulation of glutamate has been described in depression, and supersensi tivity of platelet glutamate receptors has been found in both psychotic maj or depression and schizophrenia. The aim of this study was to examine the p latelet glutamate receptor sensitivity in patients with nonpsychotic, unipo lar major depression to assess whether this is a marker of depression or of psychosis. Glutamate receptor sensitivity was assessed using the platelet intracellular calcium response to glutamate (0-100 mu mol) measured by spec trofluorometry. The depression group showed a significantly greater platele t intracellular calcium response to glutamate stimulation than the control group, both in terms of absolute values (p = 0.007) and percentage of respo nse from baseline (p = 0.030). These data suggest that platelet glutamate r eceptors may be supersensitive in depression and that the platelet may be a possible peripheral marker of glutamate function in depression.