Cytochrome P-450 epoxygenase metabolites of docosahexaenoate potently dilate coronary arterioles by activating large-conductance calcium-activated potassium channels

Dan Ye, David Zhang, Christine Oltman, Kevin Dellsperger, Hon Chi Lee, Mike Vanrollins

Research output: Contribution to journalArticle

115 Citations (Scopus)

Abstract

Diets enriched in docosahexaenoic acid, a major n-3 fatty acid in fish oil, have hypotensive properties. One mechanism that can lower blood pressure is the direct dilation of arterioles by docosahexaenoic metabolites. Vascular endothelium contains cytochrome P-450 epoxygenases that transform the n-6 fatty acid arachidonate into epoxyeicosatrienoic acids (EETs), potent dilators of coronary arterioles and activators of large-conductance calcium-activated potassium (BKCa) channels. To test whether analogous activations occur for docosahexaenoate, we compared the potency of docosahexaenoate and its five cytochrome P-450 epoxygenase metabolites, epoxydocosapentaenoates (EDPs), in dilating porcine coronary arterioles (<135 μm in diameter) precontracted with endothelin. The five EDP regioisomers had dilation EC50 values ranging from 0.5 to 24 pM (n = 5-6). In contrast, the EDP hydrolysis product 13,14-dihydroxydocosapentaenoic acid (13,14-DHDP) had an EC50 value of 30 ± 22 nM (n = 7), whereas docosahexaenoate only dilated vessels at ≥1.0 μM (n = 7). Using patch-clamp techniques in the inside-out configuration, we determined that the 13,14-EDP regioisomer potently activated (EC50 value of 6.6 ± 0.6 pM; n = 5) BKCa channels in myocytes from the porcine coronary arterioles. Moreover, 13,14-EDP potently activated BKCa channels in myocytes from rat coronary small arteries (150-300 μm in diameter); with an EC50 value of 2.2 ± 0.6 pM (n = 7), 13,14-EDP was 1000-fold more potent than EETs in activating BKCa channels. We conclude that EDPs potently dilate coronary microvessels and are the most potent fatty epoxides known to activate BKCa channels in coronary smooth muscle cells. Both actions may contribute to the hypotensive effects of dietary fish oils.

Original languageEnglish (US)
Pages (from-to)768-776
Number of pages9
JournalJournal of Pharmacology and Experimental Therapeutics
Volume303
Issue number2
DOIs
StatePublished - Nov 1 2002

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Large-Conductance Calcium-Activated Potassium Channels
Docosahexaenoic Acids
Arterioles
Cytochrome P-450 Enzyme System
Fish Oils
Muscle Cells
Dilatation
Swine
Unsaturated Dietary Fats
Acids
Epoxy Compounds
Endothelins
Vascular Endothelium
Omega-3 Fatty Acids
Patch-Clamp Techniques
Microvessels
Smooth Muscle Myocytes
Coronary Vessels
Hydrolysis
Fatty Acids

ASJC Scopus subject areas

  • Molecular Medicine
  • Pharmacology

Cite this

Cytochrome P-450 epoxygenase metabolites of docosahexaenoate potently dilate coronary arterioles by activating large-conductance calcium-activated potassium channels. / Ye, Dan; Zhang, David; Oltman, Christine; Dellsperger, Kevin; Lee, Hon Chi; Vanrollins, Mike.

In: Journal of Pharmacology and Experimental Therapeutics, Vol. 303, No. 2, 01.11.2002, p. 768-776.

Research output: Contribution to journalArticle

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abstract = "Diets enriched in docosahexaenoic acid, a major n-3 fatty acid in fish oil, have hypotensive properties. One mechanism that can lower blood pressure is the direct dilation of arterioles by docosahexaenoic metabolites. Vascular endothelium contains cytochrome P-450 epoxygenases that transform the n-6 fatty acid arachidonate into epoxyeicosatrienoic acids (EETs), potent dilators of coronary arterioles and activators of large-conductance calcium-activated potassium (BKCa) channels. To test whether analogous activations occur for docosahexaenoate, we compared the potency of docosahexaenoate and its five cytochrome P-450 epoxygenase metabolites, epoxydocosapentaenoates (EDPs), in dilating porcine coronary arterioles (<135 μm in diameter) precontracted with endothelin. The five EDP regioisomers had dilation EC50 values ranging from 0.5 to 24 pM (n = 5-6). In contrast, the EDP hydrolysis product 13,14-dihydroxydocosapentaenoic acid (13,14-DHDP) had an EC50 value of 30 ± 22 nM (n = 7), whereas docosahexaenoate only dilated vessels at ≥1.0 μM (n = 7). Using patch-clamp techniques in the inside-out configuration, we determined that the 13,14-EDP regioisomer potently activated (EC50 value of 6.6 ± 0.6 pM; n = 5) BKCa channels in myocytes from the porcine coronary arterioles. Moreover, 13,14-EDP potently activated BKCa channels in myocytes from rat coronary small arteries (150-300 μm in diameter); with an EC50 value of 2.2 ± 0.6 pM (n = 7), 13,14-EDP was 1000-fold more potent than EETs in activating BKCa channels. We conclude that EDPs potently dilate coronary microvessels and are the most potent fatty epoxides known to activate BKCa channels in coronary smooth muscle cells. Both actions may contribute to the hypotensive effects of dietary fish oils.",
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T1 - Cytochrome P-450 epoxygenase metabolites of docosahexaenoate potently dilate coronary arterioles by activating large-conductance calcium-activated potassium channels

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AU - Zhang, David

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AU - Dellsperger, Kevin

AU - Lee, Hon Chi

AU - Vanrollins, Mike

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N2 - Diets enriched in docosahexaenoic acid, a major n-3 fatty acid in fish oil, have hypotensive properties. One mechanism that can lower blood pressure is the direct dilation of arterioles by docosahexaenoic metabolites. Vascular endothelium contains cytochrome P-450 epoxygenases that transform the n-6 fatty acid arachidonate into epoxyeicosatrienoic acids (EETs), potent dilators of coronary arterioles and activators of large-conductance calcium-activated potassium (BKCa) channels. To test whether analogous activations occur for docosahexaenoate, we compared the potency of docosahexaenoate and its five cytochrome P-450 epoxygenase metabolites, epoxydocosapentaenoates (EDPs), in dilating porcine coronary arterioles (<135 μm in diameter) precontracted with endothelin. The five EDP regioisomers had dilation EC50 values ranging from 0.5 to 24 pM (n = 5-6). In contrast, the EDP hydrolysis product 13,14-dihydroxydocosapentaenoic acid (13,14-DHDP) had an EC50 value of 30 ± 22 nM (n = 7), whereas docosahexaenoate only dilated vessels at ≥1.0 μM (n = 7). Using patch-clamp techniques in the inside-out configuration, we determined that the 13,14-EDP regioisomer potently activated (EC50 value of 6.6 ± 0.6 pM; n = 5) BKCa channels in myocytes from the porcine coronary arterioles. Moreover, 13,14-EDP potently activated BKCa channels in myocytes from rat coronary small arteries (150-300 μm in diameter); with an EC50 value of 2.2 ± 0.6 pM (n = 7), 13,14-EDP was 1000-fold more potent than EETs in activating BKCa channels. We conclude that EDPs potently dilate coronary microvessels and are the most potent fatty epoxides known to activate BKCa channels in coronary smooth muscle cells. Both actions may contribute to the hypotensive effects of dietary fish oils.

AB - Diets enriched in docosahexaenoic acid, a major n-3 fatty acid in fish oil, have hypotensive properties. One mechanism that can lower blood pressure is the direct dilation of arterioles by docosahexaenoic metabolites. Vascular endothelium contains cytochrome P-450 epoxygenases that transform the n-6 fatty acid arachidonate into epoxyeicosatrienoic acids (EETs), potent dilators of coronary arterioles and activators of large-conductance calcium-activated potassium (BKCa) channels. To test whether analogous activations occur for docosahexaenoate, we compared the potency of docosahexaenoate and its five cytochrome P-450 epoxygenase metabolites, epoxydocosapentaenoates (EDPs), in dilating porcine coronary arterioles (<135 μm in diameter) precontracted with endothelin. The five EDP regioisomers had dilation EC50 values ranging from 0.5 to 24 pM (n = 5-6). In contrast, the EDP hydrolysis product 13,14-dihydroxydocosapentaenoic acid (13,14-DHDP) had an EC50 value of 30 ± 22 nM (n = 7), whereas docosahexaenoate only dilated vessels at ≥1.0 μM (n = 7). Using patch-clamp techniques in the inside-out configuration, we determined that the 13,14-EDP regioisomer potently activated (EC50 value of 6.6 ± 0.6 pM; n = 5) BKCa channels in myocytes from the porcine coronary arterioles. Moreover, 13,14-EDP potently activated BKCa channels in myocytes from rat coronary small arteries (150-300 μm in diameter); with an EC50 value of 2.2 ± 0.6 pM (n = 7), 13,14-EDP was 1000-fold more potent than EETs in activating BKCa channels. We conclude that EDPs potently dilate coronary microvessels and are the most potent fatty epoxides known to activate BKCa channels in coronary smooth muscle cells. Both actions may contribute to the hypotensive effects of dietary fish oils.

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