Antidepressant-like effect of Hoodia gordonii in a forced swimming test in mice: evidence for involvement of the monoaminergic system

Hoodia gordonii is a plant species used traditionally in southernAfrica to suppress appetite. Recently, it has been associated with a significantincrease in blood pressure and pulse rate in women, suggesting sympathomimeticactivity. The present study investigated the possible antidepressant-like effects ofacute and repeated (15 days) administration of H. gordonii extract(25 and 50 mg/kg, po) to mice exposed to a forced swimming test(FST). Neurochemical analysis of brain monoamines was also carried out to determinethe involvement of the monoaminergic system on these effects. Acute administration ofH. gordonii decreased the immobility of mice in the FST withoutaccompanying changes in general activity in the open-field test during acutetreatment, suggesting an antidepressant-like effect. The anti-immobility effect ofH. gordonii was prevented by pretreatment of mice with PCPA [aninhibitor of serotonin (5-HT) synthesis], NAN-190 (a 5-HT_1A antagonist),ritanserin (a 5-HT_2A/2C antagonist), ondansetron (a 5-HT3_Aantagonist), prazosin (an α1-adrenoceptor antagonist), {"type":"entrez-protein","attrs":{"text":"SCH23390","term_id":"1052733334","term_text":"SCH23390"}}SCH23390 (a D₁receptor antagonist), yohimbine (an α2-adrenoceptor antagonist), and sulpiride (aD₂ receptor antagonist). A significant increase in 5-HT levels in thestriatum was detected after acute administration, while 5-HT, norepinephrine anddopamine were significantly elevated after chronic treatment. Results indicated thatH. gordonii possesses antidepressant-like activity in the FST byaltering the dopaminergic, serotonergic, and noradrenergic systems.