[The messenger phosphatidylinositol and antimanic drug-antidepressants].

Inositol lipid plays a major role in cell signaling by functioning as precursors of second messengers. Phosphatidylinositol 4,5-bisphosphate, which is found in the plasma membrane, is hydrolyzed to give diacylglycerol and inositol 1,4,5-triphosphate. Diacylglycerol stimulates protein kinase C. Inositol 1,4,5-triphosphate releases calcium. Lithium inhibits the final dephosphorylation step and reduces the free inositol. This mechanism may explain the teratogenic effects of lithium. It seems that the effect of various antidepressants appear through the PI response.