Anxiolytic-like effect of chronic treatment with Erythrina velutina extract in the elevated plus-maze test.

ABSTRACT

INTRODUCTION: In Brazil, Erythrina velutina (Fabaceae) is widely used as a tranquilizer and/or sedative, and its extract exerts an anxiolytic-like effect profile in animal models, although these results may be caused by its sedative or amnesic effects. AIMS, MATERIALS AND METHODS: Thus, this study evaluated the effect of acute and chronic (23-26 days) administrations of the hydroalcoholic extract of the stem bark of Erythrina velutina (orally) in mice submitted to the following tests elevated plus-maze, forced swim, spontaneous locomotor activity, and habituation to active chamber. Chlordiazepoxide and imipramine were used as standard drugs. RESULTS: In the elevated plus-maze test, chronic, but not acute, Erythrina velutina (100mg/kg) administration increased the percentage of open arm entries, an effect also seen in both acute and chronic treatments with chlordiazepoxide (7.5mg/kg). In the forced swim test, only imipramine (25mg/kg) decreased immobility time. Impairment of habituation was seen only with acute imipramine administration and with the lowest doses of Erythrina velutina extract tested in acute (10mg/kg) and chronic (50mg/kg) administrations. CONCLUSIONS: These results suggest that chronic administration of the hydroalcoholic extract of the stem bark of Erythrina velutina exerts an anxiolytic-like effect on mice, and it could serve as a new approach for the treatment anxiety, although it may have an amnesic effect at low doses.