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

Author Andersen, Monica Levy Autor UNIFESP Google Scholar
Bignotto, Magda Autor UNIFESP Google Scholar
Tufik, Sergio Autor UNIFESP Google Scholar
Institution Universidade Federal de São Paulo (UNIFESP)
Abstract 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.
Keywords Paradoxical sleep deprivation
Sildenafil
Genital reflexes
Dopamine
Testosterone
Progesterone
Language English
Date 2007-11-01
Published in 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, impact factor)
Publisher Associação Brasileira de Divulgação Científica
Extent 1473-1480
Origin http://dx.doi.org/10.1590/S0100-879X2006005000180
Access rights Open access Open Access
Type Article
Web of Science ID WOS:000250175400008
SciELO ID S0100-879X2007001100008 (statistics in SciELO)
URI http://repositorio.unifesp.br/handle/11600/3981

Show full item record




File

Name: S0100-879X2007001100008.pdf
Size: 562.0Kb
Format: PDF
Description:
Open file

This item appears in the following Collection(s)

Search


Browse

Statistics

My Account