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

This Article Full Text Full Text (PDF) All Versions of this Article: 287/1/G151    most recent 00480.2003v1 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 ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (19) Citing Articles via Google Scholar Google Scholar Articles by Gresz, V. Articles by Nielsen, S. Search for Related Content PubMed PubMed Citation Articles by Gresz, V. Articles by Nielsen, S.

MUCOSAL BIOLOGY

Immunolocalization of AQP-5 in rat parotid and submandibular salivary glands after stimulation or inhibition of secretion in vivo

¹The Water and Salt Research Center and Institute of Anatomy, University of Aarhus, DK-8000 Aarhus C, Denmark; ²Departments of Medicine and Biological Chemistry, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205; ³School of Biological Sciences, University of Manchester, Manchester M13 9PT, United Kingdom; and ⁴Department of Biochemistry, Kyungpook National University, School of Medicine, Taegu 700-422, Korea

Submitted 12 November 2003 ; accepted in final form 12 February 2004

In vitro studies of cultured salivary gland cells and gland slices have indicated that there may be regulated translocation of aquaporin (AQP)-5 between the apical plasma membrane and intracellular compartments of the secretory cells. However, it remains unknown whether AQP-5 in salivary glands is subject to regulated trafficking in vivo. To examine this possibility, we have investigated the subcellular localization of AQP-5 in rat parotid and submandibular glands fixed in vivo under conditions of stimulated or inhibited salivary secretion. Immunofluorescence and immunoelectron microscopy was used to determine the subcellular distribution of AQP-5 in control conditions following the stimulation of secretion with pilocarpine (a muscarinic agonist) or epinephrine (an -adrenoceptor agonist) or during inhibition of basal secretion with atropine (a muscarinic antagonist) or phentolamine (an -adrenoceptor antagonist). Under control conditions, >90% of AQP-5 was associated with the apical plasma membrane of acinar and intercalated duct cells, with only rare gold particles associated with intracellular membrane domains. Pilocarpine treatment dramatically increased saliva production but had no discernible effect on AQP-5 distribution. However, the increased salivary secretion was associated with luminal dilation and the appearance of a markedly punctate AQP-5 labeling pattern due to clustering of AQP-5 at the microvilli (especially evident in the parotid gland) after 10 min of drug injection. No changes in the subcellular localization of AQP-5 were seen in response to epinephrine, atropine, or phentolamine treatment compared with control tissues. Thus AQP-5 is localized predominantly in the apical plasma membrane under control conditions, and neither the onset nor the cessation of secretion is associated in vivo with any significant short-term translocation of AQP-5 between intracellular structures and the apical plasma membrane.

aquaporin; aquaporin-5; salivary secretion; pilocarpine

This article has been cited by other articles:

				O. M. Maria, J.-W. M. Kim, J. A. Gerstenhaber, B. J. Baum, and S. D. Tran Distribution of Tight Junction Proteins in Adult Human Salivary Glands J. Histochem. Cytochem., December 1, 2008; 56(12): 1093 - 1098. [Abstract] [Full Text] [PDF]

				M. T. Skowronski, J. Lebeck, A. Rojek, J. Praetorius, E.-M. Fuchtbauer, J. Frokiaer, and S. Nielsen AQP7 is localized in capillaries of adipose tissue, cardiac and striated muscle: implications in glycerol metabolism Am J Physiol Renal Physiol, March 1, 2007; 292(3): F956 - F965. [Abstract] [Full Text] [PDF]

				C. Muller, M. Sendler, and J.-P. Hildebrandt Downregulation of aquaporins 1 and 5 in nasal gland by osmotic stress in ducklings, Anas platyrhynchos: implications for the production of hypertonic fluid J. Exp. Biol., October 15, 2006; 209(20): 4067 - 4076. [Abstract] [Full Text] [PDF]

				L. J. Dawson, P. C. Fox, and P. M. Smith Sjogrens syndrome--the non-apoptotic model of glandular hypofunction Rheumatology, July 1, 2006; 45(7): 792 - 798. [Full Text] [PDF]

				T. Matsuzaki, A. Ablimit, T. Suzuki, T. Aoki, H. Hagiwara, and K. Takata Changes of aquaporin 5-distribution during release and reaccumulation of secretory granules in isoproterenol-treated mouse parotid gland J. Electron Microsc. (Tokyo), June 1, 2006; 55(3): 183 - 189. [Abstract] [Full Text] [PDF]

				Y. Ishikawa, Z. Yuan, N. Inoue, M. T. Skowronski, Y. Nakae, M. Shono, G. Cho, M. Yasui, P. Agre, and S. Nielsen Identification of AQP5 in lipid rafts and its translocation to apical membranes by activation of M3 mAChRs in interlobular ducts of rat parotid gland Am J Physiol Cell Physiol, November 1, 2005; 289(5): C1303 - C1311. [Abstract] [Full Text] [PDF]

				A. S. Verkman More than just water channels: unexpected cellular roles of aquaporins J. Cell Sci., August 1, 2005; 118(15): 3225 - 3232. [Abstract] [Full Text] [PDF]

				S.-U. Gorr, S.G. Venkatesh, and D.S. Darling Parotid Secretory Granules: Crossroads of Secretory Pathways and Protein Storage Journal of Dental Research, June 1, 2005; 84(6): 500 - 509. [Abstract] [Full Text] [PDF]