The influence of the neuroleptic trifluoperazine on the intracellular concentration of Ca ²⁺ in macrophages of rats was studied using a Fura-2AM fluorescent Ca ²⁺ probe. It was found that trifluoperazine causes a dose-dependent increase in the intracellular Ca ²⁺ concentration associated with Ca ²⁺ mobilization from intracellular Ca ²⁺ stores and subsequent entry of Ca ²⁺ into peritoneal macrophages of rats. It was also shown that inhibitors of phospholipase A ₂ (4-bromophenacyl bromide, prednisolone, and dexamethasone), cyclooxygenases (aspirin and indomethacin), and lipoxygenases (caffeic acid, zileuton, and baicalein) suppress Ca ²⁺ responses induced by trifluoperazine in macrophages. The data obtained indicate the participation of enzymes and/or products of the cascade of arachidonic acid metabolism in the influence of trifluoperazine on the intracellular concentration of Ca ²⁺ in peritoneal macrophages.