Oxytocin induces apical and basolateral redistribution of aquaporin-2 in rat kidney.
The aquaporin-2 (AQP2) water channel is mainly located in the apical plasma membrane of collecting duct epithelial cells, but there has been some evidence of a moderate amount of basolateral localization of AQP2 at least in the inner medullary collecting duct (IMCD). Previous in vitro microperfusion studies showed that oxytocin has an antidiuretic action, most likely mediated by the vasopressin V2 receptor (V2R) in rat IMCD. By using immunohistochemistry in kidneys from male Sprague-Dawley rats, we observed acute effects of oxytocin on AQP2 localization which were prevented by a V2R antagonist. After intraperitoneal administration of oxytocin (10 U), immunohistochemistry of IMCD revealed that AQP2 was shifted from diffuse cytoplasmic localization in controls to the apical and basolateral membrane domains in oxytocin-treated rats. This pattern of AQP2 redistribution was noted in connecting tubule, cortical collecting duct and outer medullary collecting duct as well as in IMCD, although the tendency to basolateral localization was somewhat less. The pretreatment using a V2R antagonist blocked redistribution of AQP2 in response to oxytocin. We conclude that oxytocin induces a V2R-mediated redistribution of AQP2-containing cytoplasmic vesicles to both apical and basolateral plasma membrane domains in rat kidney. Oxytocin may be one of the factors that accounts for vasopressin-independent AQP2 targeting in the kidney.
Jeon
Un Sil
US
Departmentof Internal Medicine, Gyeong-sang National University, Chinju, Korea.
Joo
Kwon Wook
KW
Na
Ki Young
KY
Kim
Yon Su
YS
Lee
Jung Sang
JS
Kim
Jin
J
Kim
Gheun-Ho
GH
Nielsen
Søren
S
Knepper
Mark A
MA
Han
Jin Suk
JS
D000818:Animals; D051399:Aquaporin 2; D051400:Aquaporin 3; D051401:Aquaporin 4; D051403:Aquaporin 6; D020346:Aquaporins / Q000378:metabolism*; D007150:Immunohistochemistry; D007668:Kidney / Q000737:chemistry / Q000187:drug effects*; D007679:Kidney Medulla / Q000737:chemistry / Q000187:drug effects; D007684:Kidney Tubules / Q000737:chemistry / Q000187:drug effects; D007685:Kidney Tubules, Collecting / Q000737:chemistry / Q000187:drug effects; D008297:Male; D009994:Osmolar Concentration; D010121:Oxytocin / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011994:Recombinant Proteins / Q000494:pharmacology; D014554:Urination / Q000187:drug effects; D014556:Urine / Q000737:chemistry; D014563:Urodynamics / Q000187:drug effects
C496025:Aqp2 protein, rat; C496029:Aqp3 protein, rat; C496032:Aqp4 protein, rat; D051399:Aquaporin 2; D051401:Aquaporin 4; D051403:Aquaporin 6; D020346:Aquaporins; D011994:Recombinant Proteins; D051400:Aquaporin 3; D010121:Oxytocin