Neurobehavioural Mechanism of Antidepressant Effect of Methanol Stem Bark Extract of Adansonia digitata (Linn) in Tail Suspension Test in Mice

Akinpelu Lateef Abiola,Adesola Adedoyin,Adebayo Muritala Ayofe

doi:10.13189/app.2019.070102

Akinpelu Lateef Abiola, Adesola Adedoyin + Show 1 more

Open Access

https://doi.org/10.13189/app.2019.070102

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Abstract

Aim: An earlier study has demonstrated the in-vivo antidepressant effect of methanol stem bark extract of Adansonia digitata, using soxhlet extraction protocol, but there is a lack of scientific data on its neurobehavioural mechanism of action. This study, therefore, investigated its antidepressant potentials, using cold maceration method, and determined the probable neurobehavioural mechanism of its antidepressant-like effect. Methodology: The antidepressant-like effect of the extract was evaluated in tail suspension test, at graded doses in mice. Subsequently, the probable neurobehavioural mechanism of the antidepressant-like effect of the extract was investigated by intraperitoneal pretreatment with adrenergic, serotonergic, dopaminergic, and muscarinic cholinergic receptor antagonists; GABA agonist; nitric oxide precursor and inhibitors; and using a putative neuromodulator at NMDA receptors prior to the extract administration. Results and discussion: The extract at all the doses used, significantly (p 0.05) alteration on locomotor behaviour in mice. However, the anti-immobility potential of the extract was significantly (p<0.05) reversed by prazosin, yohimbine, sulpiride, methylene blue, L-arginine and baclofen, suggesting the involvement of adrenergic, dopaminergic, GABAerargic and nitergic pathways. Conclusion: This study, therefore, concluded that the extract may possess antidepressant effect and its mechanism may involve multiple pathways.

Highlights

According to The World Health Organization, depression is among the top ten causes of morbidity, and mortality world over [1], and it is envisaged to be the leading cause of morbidity and mortality by the year 2030 [2, 3]
Other neurotransmitters such as GABA acting via GABAB receptor [6], β adrenoceptors [7], muscarinic cholinergic receptor [8], glutaminergic via NMDA receptor [9], and nitric oxide signaling pathways [8] have been implicated in depression
The antidepressant effect of Adansonia digitata stem bark has been demonstrated using hot extraction protocol on forced swimming (FST) and tail suspension (TST) tests [21], but there is lack of scientific data on its probable neurobehavioural mechanism of action, the objective of this study was to investigate the antidepressant effect of the stem bark extract using cold extraction protocol, as well as determine its neurobehavioural mechanism of action in TST

Summary

Introduction

According to The World Health Organization, depression is among the top ten causes of morbidity, and mortality world over [1], and it is envisaged to be the leading cause of morbidity and mortality by the year 2030 [2, 3]. Patients with depression have symptoms that reflect a functional deficit in brain monoamine neurotransmitters, norepinephrine, serotonergic [4] and dopaminergic systems [5]. Despite the availability of synthetic antidepressant drugs, depression remains a major medical problem [10]. This is because the currently available antidepressant drugs are associated with a numerous side effect which includes weight gain, hypopiesia, sexual dysfunction, and cardiac toxicity and sleep disorder [11, 12, 13]. Among the demonstrated herbal therapies effective for the treatment of depression are Hypericum perforatum L. [15], Cordyceps sinensis [16], and Perilla frutescens [17]

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