Expression and Translocation of Aquaporin (AQP)-1 after Pelvic Nerve Stimulation in Rat Vagina / 대한남성과학회지

ABSTRACT

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. RESULTS: Immunolabeling showed that AQP-1 was mainly expressed in the capillaries and venules of the vagina. The translocation of AQP-1 isoforms from the cytosolic compartment to the plasma membrane compartment was observed right after nerve stimulation and had declined at 5 minutes after nerve stimulation. However, when the nerve stimulation was repeated 3 times, the translocation of AQP-1 from the intracellular membrane compartment to the plasma membrane compartment was still observed at 5 minutes. CONCLUSIONS: This study suggests that sexual arousal induced by pelvic nerve stimulation modulates AQP-1 activity in the rat vagina. This result implies that AQP-1 may play an important role in vaginal lubrication.