Purpose: Aquaporins (AQPs) are membrane proteins that facilitate water movement across biological membranes. The purposes of this study were to investigate the localization and functional roles of AQP-1 water channels in rat vagina. Materials and Methods: Female Sprague-Dawley rats (230∼240 g, n=40) were anesthetized. To investigate the expression and localization of AQPs in the vagina, the vaginal branch of the pelvic nerve was stimulated for 60 seconds (10 V, 16 Hz, 0.8 msec), and then the animals were sacrificed immediately or 5 minutes later. The expression and cellular localization of AQP-1 in the vaginal tissue was measured by Western blot and immunohistochemistry. The cytosolic (or intracellular membrane) and plasma membrane fractions of AQP-1 in vaginal tissue were studied by immunoblot analysis.