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

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

Autor Andersen, Monica Levy Autor UNIFESP Google Scholar
Bignotto, Magda Autor UNIFESP Google Scholar
Tufik, Sergio Autor UNIFESP Google Scholar
Instituição Universidade Federal de São Paulo (UNIFESP)
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.
Palavra-chave Paradoxical sleep deprivation
Sildenafil
Genital reflexes
Dopamine
Testosterone
Progesterone
Idioma Inglês
Data de publicação 2007-11-01
Publicado em Brazilian Journal of Medical and Biological Research. Associação Brasileira de Divulgação Científica, v. 40, n. 11, p. 1473-1480, 2007.
ISSN 0100-879X (Sherpa/Romeo, fator de impacto)
Publicador Associação Brasileira de Divulgação Científica
Extensão 1473-1480
Fonte http://dx.doi.org/10.1590/S0100-879X2006005000180
Direito de acesso Acesso aberto Open Access
Tipo Artigo
Web of Science WOS:000250175400008
SciELO S0100-879X2007001100008 (estatísticas na SciELO)
Endereço permanente http://repositorio.unifesp.br/handle/11600/3981

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