Effects of beta-carboline harmine on behavioral and physiological parameters observed in the chronic mild stress model: further evidence of antidepressant properties.

The chronic mild stress (CMS) model has been used as an animal model of depression which induces anhedonic behavior in rodents. The present study was aimed to evaluate the behavioral and physiological effects of administration of beta-carboline harmine in rats exposed to CMS procedure. To this aim, after 40 days of exposure to CMS procedure, rats were treated with harmine (15 mg/kg/day) for 7 days. In this study, sweet food consumption, adrenal gland weight, adrenocorticotrophin hormone (ACTH) levels, and hippocampal brain-derived-neurotrophic factor (BDNF) protein levels were assessed. Our findings demonstrated that chronic stressful situations induced anhedonia, hypertrophy of adrenal gland weight, increase ACTH circulating levels in rats and increase BDNF protein levels. Interestingly, treatment with harmine reversed anhedonia, the increase of adrenal gland weight, normalized ACTH circulating levels and BDNF protein levels. Finally, these findings further support the hypothesis that harmine could be a new pharmacological tool for the treatment of depression.