IntroductionNitric oxide synthases (NOSs) and estrogen receptors are expressed in the vagina. AimWe aimed to assess the impact of sildenafil on vaginal lubrication according to the hormonal status and to determine the role of the neuronal isoform of NOS (nNOS). MethodsFourweekold C57/BL6 female mice were sham operated or ovariectomized. At 10 weeks of age, they were injected intraperitoneally by any combination of sildenafil, 7nitroindazole (7NI)—a potent selective nNOS inhibitor—or the corresponding vehicles. Vaginal lubrication was induced in a physiological manner by cervical vaginal probing and quantified depending on the hormonal and pharmacological conditions. The animals were then sacrificed for vaginal histomorphometry. Main Outcome MeasuresThe main outcome measure is the quantification of vaginal transudate after cervicovaginal stimulation and vaginal histomorphometry. ResultsSildenafil increased cervicovaginal probinginduced vaginal lubrication in ovariectomized and shamoperated animals. Ovariectomized mice exhibited decreased vaginal lubrication as compared with shamoperated mice. When taking into account the presence of severe vaginal atrophy, a threefold increase in transudate per gram of vagina wet weight was revealed in ovariectomized animals. Castration markedly reduced the thickness of the vaginal wall. nNOS inhibition by 7NI had no impact on vaginal lubrication. ConclusionsIrrespective of the hormonal status, sildenafil increased vaginal lubrication. The vaginal effect of sildenafil was independent of the nNOS pathway and more pronounced in ovariectomized animals.