Adrenergic Control of Red Cell pH in Salmonid Fish: Roles of the Sodium/Proton Exchange, Jacobs-Stewart Cycle and Membrane Potential
We investigated the mechanisms by which adrenergic activation of sodium/proton exchange reduces the pH gradient across the membrane of rainbow trout red cells. In untreated cells, adrenergic stimulation caused a significant increase in the proton distribution ratio ([H+]e/[H+] i ) across the red cel...
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fthighwire:oai:open-archive.highwire.org:jexbio:154/1/257 2023-05-15T15:52:45+02:00 Adrenergic Control of Red Cell pH in Salmonid Fish: Roles of the Sodium/Proton Exchange, Jacobs-Stewart Cycle and Membrane Potential NIKINMAA, MIKKO TIIHONEN, KIRSTI PAAJASTE, MARITA 1990-11-01 00:00:00.0 text/html http://jeb.biologists.org/cgi/content/short/154/1/257 en eng Company of Biologists http://jeb.biologists.org/cgi/content/short/154/1/257 Copyright (C) 1990, Company of Biologists Journal Articles TEXT 1990 fthighwire 2013-04-02T07:29:35Z We investigated the mechanisms by which adrenergic activation of sodium/proton exchange reduces the pH gradient across the membrane of rainbow trout red cells. In untreated cells, adrenergic stimulation caused a significant increase in the proton distribution ratio ([H+]e/[H+] i ) across the red cell membrane. The increase in the proton distribution ratio caused by adrenergic stimulation was inhibited by the protonophore 2,4-dinitrophenol (2,4-DNP). Thus, sodium/proton exchange displaces protons from electrochemical equilibrium. Active regulation of intracellular pH by sodium/proton exchange is possible, because the extracellular dehydration of carbonic acid to carbon dioxide is uncatalyzed. The increase in proton distribution ratio caused by adrenergic stimulation was inhibited in red cell suspensions to which extracellular carbonic anhydrase had been added before stimulation. In contrast, inhibition of intracellular carbonic anhydrase markedly increased the pH changes induced by adrenergic stimulation, suggesting that the net direction of the intracellular hydration/dehydration reaction may markedly affect the intracellular pH changes. Membrane potential changes are not a necessary component of the adrenergic response. The increases in red cell volume and sodium and chloride concentrations induced by adrenergic stimulation were unaffected in cells voltage-clamped by valinomycin. Text Carbonic acid HighWire Press (Stanford University) |
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Journal Articles NIKINMAA, MIKKO TIIHONEN, KIRSTI PAAJASTE, MARITA Adrenergic Control of Red Cell pH in Salmonid Fish: Roles of the Sodium/Proton Exchange, Jacobs-Stewart Cycle and Membrane Potential |
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Journal Articles |
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We investigated the mechanisms by which adrenergic activation of sodium/proton exchange reduces the pH gradient across the membrane of rainbow trout red cells. In untreated cells, adrenergic stimulation caused a significant increase in the proton distribution ratio ([H+]e/[H+] i ) across the red cell membrane. The increase in the proton distribution ratio caused by adrenergic stimulation was inhibited by the protonophore 2,4-dinitrophenol (2,4-DNP). Thus, sodium/proton exchange displaces protons from electrochemical equilibrium. Active regulation of intracellular pH by sodium/proton exchange is possible, because the extracellular dehydration of carbonic acid to carbon dioxide is uncatalyzed. The increase in proton distribution ratio caused by adrenergic stimulation was inhibited in red cell suspensions to which extracellular carbonic anhydrase had been added before stimulation. In contrast, inhibition of intracellular carbonic anhydrase markedly increased the pH changes induced by adrenergic stimulation, suggesting that the net direction of the intracellular hydration/dehydration reaction may markedly affect the intracellular pH changes. Membrane potential changes are not a necessary component of the adrenergic response. The increases in red cell volume and sodium and chloride concentrations induced by adrenergic stimulation were unaffected in cells voltage-clamped by valinomycin. |
format |
Text |
author |
NIKINMAA, MIKKO TIIHONEN, KIRSTI PAAJASTE, MARITA |
author_facet |
NIKINMAA, MIKKO TIIHONEN, KIRSTI PAAJASTE, MARITA |
author_sort |
NIKINMAA, MIKKO |
title |
Adrenergic Control of Red Cell pH in Salmonid Fish: Roles of the Sodium/Proton Exchange, Jacobs-Stewart Cycle and Membrane Potential |
title_short |
Adrenergic Control of Red Cell pH in Salmonid Fish: Roles of the Sodium/Proton Exchange, Jacobs-Stewart Cycle and Membrane Potential |
title_full |
Adrenergic Control of Red Cell pH in Salmonid Fish: Roles of the Sodium/Proton Exchange, Jacobs-Stewart Cycle and Membrane Potential |
title_fullStr |
Adrenergic Control of Red Cell pH in Salmonid Fish: Roles of the Sodium/Proton Exchange, Jacobs-Stewart Cycle and Membrane Potential |
title_full_unstemmed |
Adrenergic Control of Red Cell pH in Salmonid Fish: Roles of the Sodium/Proton Exchange, Jacobs-Stewart Cycle and Membrane Potential |
title_sort |
adrenergic control of red cell ph in salmonid fish: roles of the sodium/proton exchange, jacobs-stewart cycle and membrane potential |
publisher |
Company of Biologists |
publishDate |
1990 |
url |
http://jeb.biologists.org/cgi/content/short/154/1/257 |
genre |
Carbonic acid |
genre_facet |
Carbonic acid |
op_relation |
http://jeb.biologists.org/cgi/content/short/154/1/257 |
op_rights |
Copyright (C) 1990, Company of Biologists |
_version_ |
1766387858805882880 |