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A Model for Fluid Secretion in Rhodnius Upper Malpighian Tubules (UMT)

A Model for Fluid Secretion in Rhodnius Upper Malpighian Tubules (UMT) We have measured fluid secretion rate in Rhodnius prolixus upper Malpighian tubules (UMT) stimulated to secrete with 5-OH-tryptamine. We used double perfusions in order to have access separately to the basolateral and to the apical cell membranes. Thirteen pharmacological agents were applied: ouabain, Bafilomycin A1, furosemide, bumetanide, DIOA, Probenecid, SITS, acetazolamide, amiloride, DPC, BaCl2, pCMBS and DTT. These agents are known to block different ion transport functions, namely ATPases, co- and/or counter-transporters and ion and water channels. The basic assumption is that water movement changes reflect changes in ion transport mechanisms, which we localize as follows: (i) At the basolateral cell membrane, fundamental are a Na+-K+-2Cl− cotransporter and a Cl−-HCO 3 − exchanger; of intermediate importance are the Na+-K+-ATPase, Cl− channels and Rp-MIP water channels; K+ channels play a lesser role: (ii) At the apical cell membrane, most important are a K+-Cl− cotransport that is being located for the first time, a V-H+-ATPase; and a Na+-H+ exchanger; a urate-anion exchanger and K+ channels are less important, while Cl− channels are not important at all. A tentative model for the function of the UMT cell is presented. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png The Journal of Membrane Biology Springer Journals

A Model for Fluid Secretion in Rhodnius Upper Malpighian Tubules (UMT)

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References (99)

Publisher
Springer Journals
Copyright
Copyright © 2004 by Springer Science+Business Media, Inc.
Subject
Life Sciences; Human Physiology; Biochemistry, general
ISSN
0022-2631
eISSN
1432-1424
DOI
10.1007/s00232-004-0723-6
pmid
15702374
Publisher site
See Article on Publisher Site

Abstract

We have measured fluid secretion rate in Rhodnius prolixus upper Malpighian tubules (UMT) stimulated to secrete with 5-OH-tryptamine. We used double perfusions in order to have access separately to the basolateral and to the apical cell membranes. Thirteen pharmacological agents were applied: ouabain, Bafilomycin A1, furosemide, bumetanide, DIOA, Probenecid, SITS, acetazolamide, amiloride, DPC, BaCl2, pCMBS and DTT. These agents are known to block different ion transport functions, namely ATPases, co- and/or counter-transporters and ion and water channels. The basic assumption is that water movement changes reflect changes in ion transport mechanisms, which we localize as follows: (i) At the basolateral cell membrane, fundamental are a Na+-K+-2Cl− cotransporter and a Cl−-HCO 3 − exchanger; of intermediate importance are the Na+-K+-ATPase, Cl− channels and Rp-MIP water channels; K+ channels play a lesser role: (ii) At the apical cell membrane, most important are a K+-Cl− cotransport that is being located for the first time, a V-H+-ATPase; and a Na+-H+ exchanger; a urate-anion exchanger and K+ channels are less important, while Cl− channels are not important at all. A tentative model for the function of the UMT cell is presented.

Journal

The Journal of Membrane Biology – Springer Journals

Published: Jan 1, 2004

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