QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

First published online June 16, 2004
Journal of Experimental Biology 207, 2599-2609 (2004)
Published by The Company of Biologists 2004
doi: 10.1242/jeb.01058

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal 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 Google Scholar Google Scholar Articles by Ianowski, J. P. Articles by O'Donnell, M. J. Search for Related Content PubMed PubMed Citation Articles by Ianowski, J. P. Articles by O'Donnell, M. J. Social Bookmarking                         What's this?

Basolateral ion transport mechanisms during fluid secretion by Drosophila Malpighian tubules: Na⁺ recycling, Na⁺:K⁺:2Cl^– cotransport and Cl^– conductance

Juan P. Ianowski and Michael J. O'Donnell^*

Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada, L8S 4K1

^* Author for correspondence (e-mail: odonnell{at}mcmaster.ca)

Accepted 28 April 2004

Mechanisms of ion transport during primary urine formation by the Malpighian tubule of Drosophila melanogaster were analyzed through measurements of fluid secretion rate, transepithelial ion flux, basolateral membrane potential (V_bl) and intracellular activities of K⁺ (a_Kⁱ) and Cl^– (a_Clⁱ). Calculation of the electrochemical potentials for both ions permitted assessment of the possible contributions of K⁺ channels, Na⁺:K⁺:2Cl^– cotransport, and K⁺:Cl^– cotransport, to net transepithelial ion secretion across the basolateral membrane. The data show that passive movement of both K⁺ and Cl^– from cell to bath is favoured across the basolateral membrane, indicating that both ions are actively transported into the cell. Contributions of basolateral K⁺ channels or K⁺:Cl^– cotransporters to net transepithelial ion secretion can be ruled out. After prior exposure of tubules to ouabain, subsequent addition of bumetanide reduced fluid secretion rate, K⁺ flux and Na⁺ flux, indicating a role for a Na⁺:K⁺:2Cl^– cotransporter in fluid secretion. Addition of the K⁺ channel blocker Ba²⁺ had no effect on a_Kⁱ or a_Clⁱ. Addition of Ba²⁺ unmasked a basolateral Cl^– conductance and the hyperpolarization of V_bl in response to Ba²⁺ was Cl^–-dependent. A new model for fluid secretion proposes that K⁺ and Cl^– cross the basolateral membrane through a Na⁺-driven Na⁺:K⁺:2Cl^– cotransporter and that most of the Na⁺ that enters the cells is returned to the bath through the Na⁺/K⁺-ATPase.

Key words: Drosophila melanogaster, Malpighian tubule, ion-selective microelectrode, K⁺ conductance, Cl^– conductance, electrochemical potential, cation-coupled chloride cotransporter, intracellular K⁺ activity, intracellular Cl^– activity

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    Twitter    What's this?

This article has been cited by other articles:

				A. T. Marshall and P. L. Clode X-ray microanalysis of Rb+ entry into cricket Malpighian tubule cells via putative K+ channels J. Exp. Biol., September 15, 2009; 212(18): 2977 - 2982. [Abstract] [Full Text] [PDF]

				J. A. T. Dow Insights into the Malpighian tubule from functional genomics J. Exp. Biol., February 1, 2009; 212(3): 435 - 445. [Abstract] [Full Text] [PDF]

				K. Pfeiffer, I. Panek, U. Hoger, A. S. French, and P. H. Torkkeli Random Stimulation of Spider Mechanosensory Neurons Reveals Long-Lasting Excitation by GABA and Muscimol J Neurophysiol, January 1, 2009; 101(1): 54 - 66. [Abstract] [Full Text] [PDF]

				G. M. Coast, R. J. Nachman, and D. A. Schooley An antidiuretic peptide (Tenmo-ADFb) with kinin-like diuretic activity on Malpighian tubules of the house cricket, Acheta domesticus (L.) J. Exp. Biol., November 15, 2007; 210(22): 3979 - 3989. [Abstract] [Full Text] [PDF]

				M. L. Patrick, K. Aimanova, H. R. Sanders, and S. S. Gill P-type Na+/K+-ATPase and V-type H+-ATPase expression patterns in the osmoregulatory organs of larval and adult mosquito Aedes aegypti J. Exp. Biol., December 1, 2006; 209(23): 4638 - 4651. [Abstract] [Full Text] [PDF]

				J. M. Evans, A. K. Allan, S. A. Davies, and J. A. T. Dow Sulphonylurea sensitivity and enriched expression implicate inward rectifier K+ channels in Drosophila melanogaster renal function J. Exp. Biol., October 1, 2005; 208(19): 3771 - 3783. [Abstract] [Full Text] [PDF]

				G. M. Coast, C. S. Garside, S. G. Webster, K. M. Schegg, and D. A. Schooley Mosquito natriuretic peptide identified as a calcitonin-like diuretic hormone in Anopheles gambiae (Giles) J. Exp. Biol., September 1, 2005; 208(17): 3281 - 3291. [Abstract] [Full Text] [PDF]

				M. R. Rheault, D. M. Debicki, and M. J. O'Donnell Characterization of tetraethylammonium uptake across the basolateral membrane of the Drosophila Malpighian (renal) tubule Am J Physiol Regulatory Integrative Comp Physiol, August 1, 2005; 289(2): R495 - R504. [Abstract] [Full Text] [PDF]

				P. Igarashi Overview: Nonmammalian Organisms for Studies of Kidney Development and Disease J. Am. Soc. Nephrol., February 1, 2005; 16(2): 296 - 298. [Full Text] [PDF]