Busca avançada
Ano de início
Entree
(Referência obtida automaticamente do SciELO, por meio da informação sobre o financiamento pela FAPESP e o número do processo correspondente, incluída na publicação pelos autores.)

Effect of sildenafil (Viagra®) on the genital reflexes of paradoxical sleep-deprived male rats

Texto completo
Autor(es):
M.L. Andersen ; M. Bignotto ; S. Tufik
Número total de Autores: 3
Tipo de documento: Artigo Científico
Fonte: Brazilian Journal of Medical and Biological Research; v. 40, n. 11, p. 1473-1480, Nov. 2007.
Resumo

Since there is evidence that paradoxical sleep deprivation (PSD) elicits penile erection (PE) and ejaculation (EJ), and that the erectile response of rats is mediated by nitric oxide, the present study sought to extend the latter finding by assessing the effects of sildenafil on the genital reflexes of male Wistar rats subjected to PSD. We also determined the influence of sildenafil on hormone concentrations. In the first experiment, sildenafil at doses ranging from 0.08 to 0.32 mg/kg was administered intraperitoneally to rats that had been deprived of sleep for 4 days and to home cage controls (N = 8-10/group). The frequency of PE and EJ was measured for 60 min. PSD alone induced PE in 50% of the animals; however, a single injection of sildenafil did not significantly increase the percentage of rats displaying PE compared to PSD-saline or to home cage groups. PSD alone also induced spontaneous EJ, but this response was not potentiated by sildenafil in the dose range tested. Testosterone concentrations were significantly lower in PSD rats (137 ± 22 ng/dL) than in controls (365 ± 38 ng/dL), whereas progesterone (0.9 ± 0.1 vs 5.4 ± 1 ng/mL) and plasma dopamine (103.4 ± 30 vs 262.6 ± 77 pg/mL) increased. These changes did not occur after sildenafil treatment. The data show that although sildenafil did not alter the frequency of genital reflexes, it antagonized hormonal (testosterone and progesterone) and plasma dopamine changes induced by PSD. The stimulation of the genital reflexes by sildenafil did not result in potentiating effects in PSD rats. (AU)

Processo FAPESP: 98/14303-3 - Center for Sleep Studies
Beneficiário:Sergio Tufik
Linha de fomento: Auxílio à Pesquisa - Centros de Pesquisa, Inovação e Difusão - CEPIDs
Processo FAPESP: 01/04329-0 - Sono e cocaína
Beneficiário:Monica Levy Andersen
Linha de fomento: Bolsas no Brasil - Doutorado