RESUMO
ETHNOPHARMACOLOGICAL RELEVANCE: Piper auritum Kunth is employed as an aphrodisiac in the traditional medicine, but corroborative evidence for such effect is scarce. AIM OF THE STUDY: The pro-sexual effect of an aqueous extract of P. auritum and its possible mechanisms were analyzed in two paradigms of male sexual function. MATERIAL AND METHODS: Effects of an aqueous extract of P. auritum (PA, single administration) were investigated in the fictive ejaculation, and copulatory behavior paradigms in sexually sluggish male rats. WAY 100635 (antagonist of 5-HT1A receptors), atosiban (antagonist of oxytocinergic receptors), L-NAME (inhibitor of the nitric oxide synthase) and baclofen (antagonist of GABAB receptors) were used as pre-treatments in order to investigate the role of different neurotransmitter systems in PA actions. Chemical profile of PA was determined by Gases Chromatography and Ultra Performance Chromatography-Electrospray Ionization-Masses Spectrometry (UPLC-ESI-MS). RESULTS: In males with retarded ejaculation, PA stimulated ejaculatory behavior and recovered electromyographic activity of pelvic musculature participating in seminal emission and ejaculation. All pre-treatments blocked stimulating effects of PA on the fictive ejaculation; additionally WAY 100635 interfered with PA actions on ejaculatory behavior. Safrol, apigenin dimethylether, myristicin, vaccihein A, sakuranin and sakuranetin flavonoids, were main constituents of PA, with possible participation in its pro-sexual effects. CONCLUSIONS: Pro-sexual effects of P. auritum elicited at level of ejaculation were mediated by several neurotransmitter systems, among which serotonin and its 5-HT1A receptors play an important role. Present findings support P. auritum reputation as an aphrodisiac, with potential use in delayed ejaculation disorder.
Assuntos
Afrodisíacos/farmacologia , Piper , Extratos Vegetais/farmacologia , Comportamento Sexual/efeitos dos fármacos , Animais , Afrodisíacos/química , Comportamento Animal/efeitos dos fármacos , Ejaculação/efeitos dos fármacos , Feminino , Masculino , Compostos Fitoquímicos/análise , Compostos Fitoquímicos/farmacologia , Piper/química , Piperazinas/farmacologia , Extratos Vegetais/química , Folhas de Planta/química , Piridinas/farmacologia , Ratos Wistar , Receptor 5-HT1A de Serotonina/fisiologia , Antagonistas do Receptor 5-HT1 de Serotonina/farmacologiaRESUMO
Allopregnanolone (3α-THP) is one of the main reduced progesterone (P4) metabolites that is recognized as a neuroprotective and myelinating agent. 3α-THP also induces proliferation of different neural cells. It has been shown that P4 favors the progression of glioblastomas (GBM), the most common and aggressive primary brain tumors. However, the role of 3α-THP in the growth of GBMs is unknown. Here, we studied the effects of 3α-THP on the number of cells, proliferation and gene expression in U87 cell line derived from a human GBM. 3α-THP (10, 100nM and 1µM) increased the number of U87 cells, and at 10nM exerted a similar increase in both the number of total and proliferative U87 cells as compared with P4 (10nM). Interestingly, finasteride (F; 100nM), an inhibitor of 5α-reductase (5αR), an enzyme necessary to metabolize P4 and produce 3α-THP, blocked the increase in the number of U87 cells induced by P4. By using RT-qPCR, we determined that U87 cells express 5α-R isoenzymes 1 and 2 (5αR1 and 5αR2), being 5αR1 the predominant one in these cells. 3α-THP (10nM) increased the expression of TGFß1, EGFR, VEGF and cyclin D1 genes. P4 increased TGFß1 and EGFR expression, and this effect was blocked by F. These data provide evidence that P4, through its metabolite 3α-THP, can promote in part cell proliferation of human GBM cells by changing the expression of genes involved in tumor progression.