Guibourtia tessmannii -induced fictive ejaculation in spinal male rat: involvement of D ₁ , D ₂ -like receptors

Abstract

Context:Guibourtia tessmannii (Caesalpiniaceae) is a plant traditionally used as aphrodisiac. We previously reported the pro-ejaculatory effects of the aqueous and methanol extracts of G. tesmannii in spinal male rat. However, the mechanism underlying such effects has not been elucidated.Objective: This study characterizes the dopaminergic sub-type receptors involved in G. tesmannii-induced ejaculation in male Wistar rat.Materials and methods: Urethane-anesthetized spinal male rats were intravenously treated with saline solution (1 mL/kg, control); dopamine (0.1 μmol/kg, reference); aqueous or methanol extracts of G. tesmannii (20 mg/kg) in the absence or presence of haloperidol (0.26 μmol/kg), a nonspecific dopaminergic receptor antagonist, Sch23390 (0.26 μmol/kg), a specific D1-like receptor antagonist or, sulpiride (0.26 μmol/kg), a specific D2-like receptor antagonist. Electromyography of the bulbospongiosus muscles and intraseminal pressure were recorded after urethral, penile and drug stimulations.Results: Urethral and penile stimulations, intravenous injection of dopamine or, aqueous and methanol extracts of G. tesmannii always triggered the expression of rhythmic contraction of the bulbospongiosus muscles with an average mean of 3.33 ± 0.43; 7.83 ± 0.85; 9.80 ± 0.86; 0.83 ± 0.54 and 2.67 ± 0.95 contractions, respectively. The intraseminal pressure was more expressed after urethral and penile stimulations (15.66 ± 1.58 and 13.60 ± 2.40 mmHg, respectively). In rats pretreated with haloperidol, Sch23390 or sulpiride, no ejaculation was recorded after intravenous injection of G. tesmannii extracts or dopamine.Discussion and conclusion:Guibourtia tesmannii-induced ejaculation requires the integrity of D1 and D2-like receptors. These findings further justify the ethno-medicinal claims of G. tesmannii as an aphrodisiac.

In/ex copula ejaculatory activities of aqueous and methanolic extracts of Aframomum melegueta (Zingiberaceae) in sexually experienced male rat

“…It was also noticed that penile stimulation was more efficient in promising ejaculation than urethral stimulation. This observation is similar to that of previous studies (Carro‐Juarez & Rodrıguez‐Manzo, ; Watcho et al., ; Watcho, Mbiakop, et al., ; Watcho, Wankeu‐Nya, et al., ; Birri, Franco, Vallejo, Carro‐Juárez, & Agnese, ; Deeh et al., ). This pro‐ejaculatory effect of A. melegueta could be attributed to the alkaloids, saponins, tannins and triterpenes found in this plant (Voukeng et al., ).…”

“…Similar to the reference pro‐ejaculatory drug, dopamine, both aqueous and methanolic extracts of A. melegueta significantly induced the expression of the ejaculation when administered intravenously. This pro‐ejaculatory effect of A. melegueta is comparable to that of G. tessmannii (Watcho et al., ; Deeh et al., ) and M. tomentosa (Carro‐Juarez, Lobaton, Benitez, & Espiritu, ). The expression of intraseminal pressure and the contraction of the bulbospongiosus muscles recorded in this work are regarded as markers of emission and expulsion phases of ejaculation respectively.…”

“…Thereafter, one of the selected treatments was applied, and the response obtained under their influence was recorded. The intraseminal pressure and also the number, latency and frequency of contractions of the striated bulbospongiosus muscles were recorded for 5 min (Watcho et al., ; Watcho, Mbiakop, et al., ; Watcho, Wankeu‐Nya, et al., ; Kozyrev & Coolen, ; Deeh et al., ). Sensorial or pharmacological stimuli were amplified with polygraph (Biopac Student Lab PRO, version 3.7.3, frequency 50 Hz and model MP36E‐CE) and registered on computer (Watcho et al., ).…”

“…In developing countries, due to the easy availability at less cost, medicinal plants are proven effective in improving libido and sexual behaviour in males. In this regard, Montanoa tomentosa (Carro‐Juárez, Cervantes, Cervantes‐Méndez, & Rodríguez‐Manzo, ), Guibourtia tessmannii (Watcho et al., ; Deeh et al.,), Allanblanckia floribunda (Kada et al., ) and Bersama engleriana (Watcho, Mbiakop, et al., ) are reported to improve ejaculation in male rats. Aframomum melegueta used in this study is a small‐size herbaceous tree belonging to the Zingiberaceae family, widespread throughout tropical Africa and which grows by forming fruits containing seeds.…”

Mechanism of Shugan Yidan fang, a Chinese herbal formula, in rat model of premature ejaculation

“…Studies have demonstrated that D2-like receptors of DAR-D2 and D3 participate in DA secretion [ 9 ], with these receptors highly expressed on cerebral nuclei and the nucleus paraventricularis that are associated with regulation of ejaculation. Moreover, studies in rats have shown that pre-treatment of sulpiride, a non-selective DAR antagonist, avoids PE induced by several stimulants [ 10 ], while 68.8% patients with PE had a recovery after treatment with the sulpiride [ 11 ]. Therefore, we consider that D2/D3 receptors and DAT play important roles in ejaculation, and are associated with the treatment of PE.…”