HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

Am J Physiol Regul Integr Comp Physiol 293: R492-R503, 2007. First published April 18, 2007; doi:10.1152/ajpregu.00689.2005
0363-6119/07 $8.00

This Article Free upon publication Full Text Full Text (PDF) All Versions of this Article: 293/1/R492    most recent 00689.2005v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Web of Science (1) Citing Articles via Google Scholar Google Scholar Articles by Floyd, R. V. Articles by Mobasheri, A. Search for Related Content PubMed PubMed Citation Articles by Floyd, R. V. Articles by Mobasheri, A.

COMPARATIVE AND EVOLUTIONARY PHYSIOLOGY

Expression and nephron segment-specific distribution of major renal aquaporins (AQP1–4) in Equus caballus, the domestic horse

¹Department of Physiology, ²Department of Veterinary Preclinical Sciences, ³Equine Division, and ⁴Division of Small Animal Studies, Faculty of Veterinary Science, University of Liverpool, Liverpool; ⁵Institute of Membrane and Systems Biology, University of Leeds, Leeds; and ⁶Division of Veterinary Medicine, School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington, United Kingdom

Submitted 23 September 2005 ; accepted in final form 9 April 2007

Aquaporins (AQPs) play fundamental roles in water and osmolyte homeostasis by facilitating water and small solute movement across plasma membranes of epithelial, endothelial, and other tissues. AQP proteins are abundantly expressed in the mammalian kidney, where they have been shown to play essential roles in fluid balance and urine concentration. Thus far, the majority of studies on renal AQPs have been carried out in laboratory rodents and sheep; no data have been published on the expression of AQPs in kidneys of equines or other large mammals. The aim of this comparative study was to determine the expression and nephron segment localization of AQP1–4 in Equus caballus by immunoblotting and immunohistochemistry with custom-designed rabbit polyclonal antisera. AQP1 was found in apical and basolateral membranes of the proximal convoluted tubules and thin descending limbs of the loop of Henle. AQP2 expression was specifically detected in apical membranes of cortical, medullary, and papillary collecting ducts. AQP3 was expressed in basolateral membranes of cortical, medullary, and papillary collecting ducts. Immunohistochemistry also confirmed AQP4 expression in basolateral membranes of cells lining the distal convoluted and connecting tubules. Western blots revealed high expression of AQP1–4 in the equine kidney. These observations confirm that AQPs are expressed in the equine kidney and are found in similar nephron locations to mouse, rat, and human kidney. Equine renal AQP proteins are likely to be involved in acute and chronic regulation of body fluid composition and may be implicated in water balance disorders brought about by colic and endotoxemia.

equine; aquaporin; tissue microarrays; immunohistochemistry