Intracellular calcium signaling systems in the pathophysiology of affective disorders

In this report, we have studied and reviewed the nature of intracellular Ca 2+ signaling to understand what mechanism is involved in the dysfunction of this signaling system in affective disorders. In platelets of patients wit h affective disorders, serotonin (5-HT)-induced intracellular calcium (Ca2) mobilization was enhanced. Several reports from other laboratories also s uggest that 5-HT- or thrombin-induced Ca2+ mobilization is enhanced in plat elets of mood disorders. Characterization of antidepressant drugs to affect intracellular Ca2+ concentration in rat cultured neuronal cells and glioma cells was subsequently discussed. Many kinds of antidepressant drugs, for example imipramine, inhibited intracellular Ca2+ signaling in primary cultu red rat neuronal cells. Lithium attenuated the plateau phase of Ca2+ respon se in rat hippocampal slices. Verapamil inhibited the sustained Ca2+ signal ing in rat glioma cells. Thus, drugs for mood disorders appear to act on Ca 2+ signaling. These results suggest the importance to investigate intracell ular Ca2+ signaling system for understanding the pathophysiology of affecti ve disorders.