Cation fluxes in erythrocytes of patients with endogenous depression in the course of treatment with antidepressant drugs.

Erythrocyte cation fluxes were measured in 30 patients with endogenous depression, before and after 14 days of treatment with antidepressant drugs, imipramine or nomifensine. Assays were made of active (ouabain-sensitive) transport of sodium and potassium as well as of lithium-sodium countertransport, reflecting sodium exchange diffusion. All the parameters studied increased significantly on 14th day of the thymoleptic treatment. The mean increase in activity of cation fluxes was similar in patients receiving imipramine or nomifensine. Patients with good clinical response to the treatment (as rated by the reduction of the initial intensity of depression on the Hamilton Scale on 21st day of therapy) had greater increase in ouabain-sensitive sodium flux than "non-responders". A possible role of cation transport processes in the mechanism of action of antidepressant drugs is discussed.