title: Axial heterogeneity in basolateral AQP2 localization in rat kidney: effect of vasopressin.
abstract: 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. Short-term desamino-Cys(1), (D)-Arg(8) vasopressin (dDAVP) treatment (2 h) of Brattleboro rats caused no increase in AQP2 labeling of the BLM. In contrast, long-term dDAVP treatment (6 days) of Brattleboro rats caused an increased BLM labeling in CNT, CCD, and IMCD. Treatment of normal rats with V(2)-receptor antagonist for 60 min caused retrieval of AQP2 from the apical plasma membrane. Moreover, AQP2 labeling of the BLM was unchanged in CNT and IMCD but increased in CCD. In conclusion, there is an axial heterogeneity in the subcellular localization of AQP2 with prominent AQP2 labeling of the BLM in CNT and IMCD. 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.
authors.affiliation: The Water and Salt Research Center, Institute of AnatomyUniversity of DK-8000 Aarhus, Denmark.
authors.forename: Birgitte Mønster
authors.initials: BM
authors.lastname: Christensen
authors.forename: Weidong
authors.initials: W
authors.lastname: Wang
authors.forename: Jørgen
authors.initials: J
authors.lastname: Frøkiaer
authors.forename: Søren
authors.initials: S
authors.lastname: Nielsen
mesh_terms: D000818:Animals; D065092:Antidiuretic Hormone Receptor Antagonists; D051399:Aquaporin 2; D051403:Aquaporin 6; D020346:Aquaporins / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism / Q000648:ultrastructure; D003894:Deamino Arginine Vasopressin / Q000494:pharmacology; D007150:Immunohistochemistry; D007672:Kidney Cortex / Q000187:drug effects* / Q000378:metabolism* / Q000648:ultrastructure; D007684:Kidney Tubules / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D008297:Male; D051381:Rats; D011910:Rats, Brattleboro; D017208:Rats, Wistar; D012076:Renal Agents / Q000494:pharmacology; D014667:Vasopressins / Q000172:deficiency* / Q000494:pharmacology*
chemical_list: D065092:Antidiuretic Hormone Receptor Antagonists; C496025:Aqp2 protein, rat; D051399:Aquaporin 2; D051403:Aquaporin 6; D020346:Aquaporins; D012076:Renal Agents; D014667:Vasopressins; D003894:Deamino Arginine Vasopressin