Preliminary Study of Effects of Type V Phosphodiesterase Inhibitor(Vardenafil) on Oxytocin Expression in the Rat Paraventricular Nucleus / 대한남성과학회지

ABSTRACT

PURPOSE: The present study investigated the effects of the type 5 phosphodiesterase(PDE-5) inhibitor, vardenafil on oxytocin expression in the paraventricular nucleus(PVN) of the hypothalamus were investigated. MATERIALS AND METHODS: Spargue-Dawley rats received a 2-week oral treatment with vardenafil(0.25 mg/kg/day oral adminstration, n=5) or(0.5 mg/kg/day oral adminstration, n=5) or(1 mg/kg/day oral adminstration, n=5) or (2 mg/kg/day oral adminstration, n=5) or control(n=3). Oxytocin expression in the paraventricular nucleus was measured. These experiments were performed in the absence of sexual stimulation for at least 36 hours before the experiments. RESULTS: The number of oxytocin-positive cells in the PVN was 46.88+/-15.46/section in the control group, 61.42+/-26.37/section in the 0.25 mg/kg vardenafil-treated group, 78.00+/-33.44/section in the 0.5 mg/kg vardenafil-treated group, 78.81+/-37.18/section in the 1 mg/kg vardenafil-treated group and 94.61+/-57.38/section in the 2 mg/kg vardenafil-treated group. The number of oxytocin-positive cells in the PVN increased in a concentration-dependent manner. CONCLUSIONS: Daily vardenafil administration increases expression of oxytocin in the PVN in a dose-dependent fashion in the absence of sexual stimulation. Thus, these results imply that the PDE-5 inhibitor vardenafil has a direct effect on the erectile pathway in the central nervous system in the absence of sexual stimulation.