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Arachidonic Acid Inhibits Epithelial Na Channel Via Cytochrome P450 (CYP) Epoxygenase-dependent Metabolic Pathways

We used the patch-clamp technique to study the effect of arachidonic acid (AA) on epithelial Na channels (ENaC) in the rat cortical collecting duct (CCD). Application of 10 μM AA decreased the ENaC activity defined by NPo from 1.0 to 0.1. The dose–response curve of the AA effect on ENaC shows that 2...

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Autores principales: Wei, Yuan, Lin, Dao-Hong, Kemp, Rowena, Yaddanapudi, Ganesh S.S., Nasjletti, Alberto, Falck, John R., Wang, Wen-Hui
Formato: Texto
Lenguaje:English
Publicado: The Rockefeller University Press 2004
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2234027/
https://www.ncbi.nlm.nih.gov/pubmed/15545402
http://dx.doi.org/10.1085/jgp.200409140
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author Wei, Yuan
Lin, Dao-Hong
Kemp, Rowena
Yaddanapudi, Ganesh S.S.
Nasjletti, Alberto
Falck, John R.
Wang, Wen-Hui
author_facet Wei, Yuan
Lin, Dao-Hong
Kemp, Rowena
Yaddanapudi, Ganesh S.S.
Nasjletti, Alberto
Falck, John R.
Wang, Wen-Hui
author_sort Wei, Yuan
collection PubMed
description We used the patch-clamp technique to study the effect of arachidonic acid (AA) on epithelial Na channels (ENaC) in the rat cortical collecting duct (CCD). Application of 10 μM AA decreased the ENaC activity defined by NPo from 1.0 to 0.1. The dose–response curve of the AA effect on ENaC shows that 2 μM AA inhibited the ENaC activity by 50%. The effect of AA on ENaC is specific because neither 5,8,11,14-eicosatetraynoic acid (ETYA), a nonmetabolized analogue of AA, nor 11,14,17-eicosatrienoic acid mimicked the inhibitory effect of AA on ENaC. Moreover, inhibition of either cyclooxygenase (COX) with indomethacin or cytochrome P450 (CYP) ω-hydroxylation with N-methylsulfonyl-12,12-dibromododec-11-enamide (DDMS) failed to abolish the effect of AA on ENaC. In contrast, the inhibitory effect of AA on ENaC was absent in the presence of N-methylsulfonyl-6-(propargyloxyphenyl)hexanamide (MS-PPOH), an agent that inhibits CYP-epoxygenase activity. The notion that the inhibitory effect of AA is mediated by CYP-epoxygenase–dependent metabolites is also supported by the observation that application of 200 nM 11,12-epoxyeicosatrienoic acid (EET) inhibited ENaC in the CCD. In contrast, addition of 5,6-, 8,9-, or 14,15-EET failed to decrease ENaC activity. Also, application of 11,12-EET can still reduce ENaC activity in the presence of MS-PPOH, suggesting that 11,12-EET is a mediator for the AA-induced inhibition of ENaC. Furthermore, gas chromatography mass spectrometry analysis detected the presence of 11,12-EET in the CCD and CYP2C23 is expressed in the principal cells of the CCD. We conclude that AA inhibits ENaC activity in the CCD and that the effect of AA is mediated by a CYP-epoxygenase–dependent metabolite, 11,12-EET.
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spelling pubmed-22340272008-03-21 Arachidonic Acid Inhibits Epithelial Na Channel Via Cytochrome P450 (CYP) Epoxygenase-dependent Metabolic Pathways Wei, Yuan Lin, Dao-Hong Kemp, Rowena Yaddanapudi, Ganesh S.S. Nasjletti, Alberto Falck, John R. Wang, Wen-Hui J Gen Physiol Article We used the patch-clamp technique to study the effect of arachidonic acid (AA) on epithelial Na channels (ENaC) in the rat cortical collecting duct (CCD). Application of 10 μM AA decreased the ENaC activity defined by NPo from 1.0 to 0.1. The dose–response curve of the AA effect on ENaC shows that 2 μM AA inhibited the ENaC activity by 50%. The effect of AA on ENaC is specific because neither 5,8,11,14-eicosatetraynoic acid (ETYA), a nonmetabolized analogue of AA, nor 11,14,17-eicosatrienoic acid mimicked the inhibitory effect of AA on ENaC. Moreover, inhibition of either cyclooxygenase (COX) with indomethacin or cytochrome P450 (CYP) ω-hydroxylation with N-methylsulfonyl-12,12-dibromododec-11-enamide (DDMS) failed to abolish the effect of AA on ENaC. In contrast, the inhibitory effect of AA on ENaC was absent in the presence of N-methylsulfonyl-6-(propargyloxyphenyl)hexanamide (MS-PPOH), an agent that inhibits CYP-epoxygenase activity. The notion that the inhibitory effect of AA is mediated by CYP-epoxygenase–dependent metabolites is also supported by the observation that application of 200 nM 11,12-epoxyeicosatrienoic acid (EET) inhibited ENaC in the CCD. In contrast, addition of 5,6-, 8,9-, or 14,15-EET failed to decrease ENaC activity. Also, application of 11,12-EET can still reduce ENaC activity in the presence of MS-PPOH, suggesting that 11,12-EET is a mediator for the AA-induced inhibition of ENaC. Furthermore, gas chromatography mass spectrometry analysis detected the presence of 11,12-EET in the CCD and CYP2C23 is expressed in the principal cells of the CCD. We conclude that AA inhibits ENaC activity in the CCD and that the effect of AA is mediated by a CYP-epoxygenase–dependent metabolite, 11,12-EET. The Rockefeller University Press 2004-12 /pmc/articles/PMC2234027/ /pubmed/15545402 http://dx.doi.org/10.1085/jgp.200409140 Text en Copyright © 2004, The Rockefeller University Press This article is distributed under the terms of an Attribution–Noncommercial–Share Alike–No Mirror Sites license for the first six months after the publication date (see http://www.rupress.org/terms). After six months it is available under a Creative Commons License (Attribution–Noncommercial–Share Alike 4.0 Unported license, as described at http://creativecommons.org/licenses/by-nc-sa/4.0/).
spellingShingle Article
Wei, Yuan
Lin, Dao-Hong
Kemp, Rowena
Yaddanapudi, Ganesh S.S.
Nasjletti, Alberto
Falck, John R.
Wang, Wen-Hui
Arachidonic Acid Inhibits Epithelial Na Channel Via Cytochrome P450 (CYP) Epoxygenase-dependent Metabolic Pathways
title Arachidonic Acid Inhibits Epithelial Na Channel Via Cytochrome P450 (CYP) Epoxygenase-dependent Metabolic Pathways
title_full Arachidonic Acid Inhibits Epithelial Na Channel Via Cytochrome P450 (CYP) Epoxygenase-dependent Metabolic Pathways
title_fullStr Arachidonic Acid Inhibits Epithelial Na Channel Via Cytochrome P450 (CYP) Epoxygenase-dependent Metabolic Pathways
title_full_unstemmed Arachidonic Acid Inhibits Epithelial Na Channel Via Cytochrome P450 (CYP) Epoxygenase-dependent Metabolic Pathways
title_short Arachidonic Acid Inhibits Epithelial Na Channel Via Cytochrome P450 (CYP) Epoxygenase-dependent Metabolic Pathways
title_sort arachidonic acid inhibits epithelial na channel via cytochrome p450 (cyp) epoxygenase-dependent metabolic pathways
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2234027/
https://www.ncbi.nlm.nih.gov/pubmed/15545402
http://dx.doi.org/10.1085/jgp.200409140
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