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

Abstract

Hoodia gordonii is a plant species used traditionally in southern Africa to suppress appetite. Recently, it has been associated with a significant increase in blood pressure and pulse rate in women, suggesting sympathomimetic activity. The present study investigated the possible antidepressant-like effects of acute 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 determine the involvement of the monoaminergic system on these effects. Acute administration of H. gordonii decreased the immobility of mice in the FST without accompanying changes in general activity in the open-field test during acute treatment, suggesting an antidepressant-like effect. The anti-immobility effect of H. gordonii was prevented by pretreatment of mice with PCPA [an inhibitor of serotonin (5-HT) synthesis], NAN-190 (a 5-HT1A antagonist), ritanserin (a 5-HT2A/2C antagonist), ondansetron (a 5-HT3A antagonist), prazosin (an α1-adrenoceptor antagonist), SCH23390 (a D1 receptor antagonist), yohimbine (an α2-adrenoceptor antagonist), and sulpiride (a D2 receptor antagonist). A significant increase in 5-HT levels in the striatum was detected after acute administration, while 5-HT, norepinephrine and dopamine were significantly elevated after chronic treatment. Results indicated that H. gordonii possesses antidepressant-like activity in the FST by altering the dopaminergic, serotonergic, and noradrenergic systems.

Evidence for the involvement of the monoaminergic system in the antidepressant-like activity of methanolic extract of Bacopa monnieri in albino mice

“…4 CNS stimulant drugs, such as cocaine or amphetamines, can decrease the duration of immobility in the FST. 31 As opposed to the action of antidepressants; this is due to the CNS stimulant action, which brings about marked motor stimulation, resulting in an increased general activity of animals. Such psycho stimulant actions of drugs can produce a false-positive effect in the FST model.…”

Protective Effect of Sphaerococcus coronopifolius Crude Extract in Combination with Bacillus Calmette-Guerin on Ligature-Induced Depression in Female Wistar Rats

“…The open field test (OFT) is used in combination with the FST to discard non-specific actions of antidepressant treatments. 51 It was reported that drugs inducing increase in motor activity may give a 'false' positive effect. 52 This test evaluates the reaction of an animal towards a new and spacious environment.…”

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“…This hypothesis seems to be strengthened by the mechanism of antidepressant drugs, which raise all these neurotransmitter levels in the brain. And also stated that the FST affords a suitable model for exploring neurobiological mechanisms for antidepressant effects 17,18 . Therefore we conducted the study to show the role of serotonergic, noradrenergic, and opioid systems on the effects of AEAES.…”