Resumen

URBINA, Mary et al. Síntesis de serotonina y presencia de hidroxilasa de triptófano en linfocitos de pacientes con depresión mayor tratados con fluoxetina y ácido fólico. AVFT [online]. 2008, vol.27, n.2, pp.114-120. ISSN 0798-0264.

Folic acid has been used as a coadjuvant of antidepressant treatment, and low levels have been reported in depressed patients. Due to the role of folic acid and the relevance of serotonergic system in lymphocytes during depression, the aim of this study is to explore the capacity for serotonin production and the presence of tryptophan hydroxylase in lymphocytes of patients treated with fluoxetine and folic acid. Patients were diagnosed by the criteria of Diagnostic and Statistical Manual of the American Psychiatric Association, the severity of the depressive episode was evaluated by Hamilton Scale for Depression. Twenty seven patients (21-58 years) selected did not present other disorder neither risk of suicide. They were randomly distributed, some (14) received 20 mg/d of fluoxetine plus 10 mg/d folic acid, and others (13) fluoxetine and placebo. Control group was composed by 15 apparently healthy subjects (26-49 years). Ten patients from each experimental group finished the study. Blood samples were taken prior and six weeks after treatment. Plasma homocysteine decreased with folic acid. Lymphocytes were isolated by density gradients with Ficoll/Hypaque and differential adhesion to plastic. Serotonin concentration was not different between the two groups and neither respecting controls, but it was low in those that received treatment. Serotonin synthesis from tryptophan was lower in patients than in controls and decreased in patients after the treatments. The number of lymphocytes with the enzyme was lower in patients and decreased after folic acid. The results could be in agreement with the monoaminergic hypothesis of depression, in which modifications of central and peripheral serotonin systems take place. Decreases of serotonin concentration after treatments and of its synthesis before treatment might indicate modulations in relation to lymphocyte function in depressed.

Palabras clave : folic acid; major depression; lymphocytes; serotonin; serotonin synthesis; tryptophan hydroxylase.