Role of Monoaminergic System in the Etiology of Olive Oil Induced Antidepressant and Anxiolytic Effects in Rats

Olive oil is the major component of the Mediterranean diet and has rich history of nutritional and medicinal uses. In the present study, the antidepressant and anxiolytic effects and their neurochemical basis following repeated administration of extravirgin olive oil were monitored. Male albino Wistar rats were used during study. Animals of test group were given olive oil orally at the dose of 0.25 mL/kg daily for 4 weeks. Control rats received equal volume of water. Elevated-plus maze (EPM) test and forced swim test (FST) were performed for the assessment of anxiety and depression like symptoms. An increase in time spent in open arm in EPM and increased struggling time in FST following long-term administration of olive oil indicate that olive oil has anxiolytic and antidepressant properties. Neurochemical results showed that repeated administration of olive oil decreased the levels of brain 5-HT (5-hydroxytryptamine), 5-HIAA (5-hydroxyindoleacetic acid), and levels of DA (dopamine); however, levels of DA metabolite HVA (homovalinic acid) were increased. Hence, present findings suggest that olive oil has neuroprotective effects. It reduces behavioral deficits via altering 5-HT and DA metabolism. So it could be used as a therapeutic substance for the treatment of depression and anxiety.