American journal of physiology. Renal physiology
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Am. J. Physiol. Renal Physiol. · Apr 2003
Axial heterogeneity in basolateral AQP2 localization in rat kidney: effect of vasopressin.
The purpose of the present study was to examine whether there is axial heterogeneity in the basolateral plasma membrane (BLM) localization of AQP2 and whether altered vasopressin action or medullary tonicity affects the BLM localization of AQP2. Immunocytochemistry and immunoelectron microscopy revealed AQP2 labeling of the BLM in connecting tubule (CNT) cells and inner medullary collecting duct (IMCD) principal cells in normal rats and vasopressin-deficient Brattleboro rats. In contrast there was little basolateral AQP2 labeling in cortical (CCD) and outer medullary collecting duct principal cells. ⋯ There was no increase in AQP2 labeling of the BLM in response to short-term dDAVP. Moreover, acute V(2)-receptor antagonist treatment did not cause retrieval of AQP2 from the BLM. In contrast, long-term dDAVP treatment caused a major increase in AQP2 expression in the BLM in CCD.