A role for the sodium pump in H2O2-induced vasorelaxation in porcine isolated coronary arteries
Hydrogen peroxide (H2O2) has been proposed to act as a factor for endothelium-derived hyperpolar-ization (EDH) and EDH may act as a ‘back up’ system to compensate the loss of the NO pathway. Here,the mechanism of action of H2O2in porcine isolated coronary arteries (PCAs) was investigated. DistalPCAs...
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Elsevier
2014
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| Online Access: | https://eprints.nottingham.ac.uk/35683/ |
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| author | Wong, P.S. Garle, M.J. Alexander, S.P.H. Randall, M.D. Roberts, R.E. |
| author_facet | Wong, P.S. Garle, M.J. Alexander, S.P.H. Randall, M.D. Roberts, R.E. |
| author_sort | Wong, P.S. |
| building | Nottingham Research Data Repository |
| collection | Online Access |
| description | Hydrogen peroxide (H2O2) has been proposed to act as a factor for endothelium-derived hyperpolar-ization (EDH) and EDH may act as a ‘back up’ system to compensate the loss of the NO pathway. Here,the mechanism of action of H2O2in porcine isolated coronary arteries (PCAs) was investigated. DistalPCAs were mounted in a wire myograph and pre-contracted with U46619 (1 nM–50 muM), a throm-boxane A2-mimetic or KCl (60 mM). Concentration–response curves to H2O2(1 muM–1 mM), bradykinin(0.01 nM–1 muM), sodium nitroprusside (SNP) (10 nM–10 muM), verapamil (1 nM–10 muM), KCl (0–20 mM)or Ca2+-reintroduction (1 muM–10 mM) were constructed in the presence of various inhibitors. Activityof the Na+/K+-pump was measured through rubidium-uptake using atomic absorption spectropho-tometry. H2O2caused concentration-dependent vasorelaxations with a maximum relaxation (Rmax) of100 ± 16% (mean ± SEM), pEC50= 4.18 ± 0.20 (n = 4) which were significantly inhibited by PEG-catalase at0.1–1.0 mM H2O2(P < 0.05). 10 mM TEA significantly inhibited the relaxation up to 100 muM H2O2(P < 0.05).60 mM K+and 500 nM ouabain significantly inhibited H2O2-induced vasorelaxation producing a relax-ation of 40.8 ± 8.5% (n = 5) and 47.5 ± 8.6% (n = 6) respectively at 1 mM H2O2(P < 0.0001). H2O2-inducedvasorelaxation was unaffected by the removal of endothelium, inhibition of NO, cyclo-oxygenase, gapjunctions, SKCa, IKCa, BKCaKir, KV, KATPor cGMP. 100 muM H2O2had no effects on the KCl-induced vasore-laxation or Ca2+-reintroduction contraction. 1 mM H2O2inhibited both KCl-induced vasorelaxation andrubidium-uptake consistent with inhibition of the Na+/K+-pump activity. We have shown that the vas-cular actions of H2O2are sensitive to ouabain and high concentrations of H2O2are able to modulate theNa+/K+-pump. This may contribute towards its vascular actions. |
| first_indexed | 2025-11-14T19:27:18Z |
| format | Article |
| id | nottingham-35683 |
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| publishDate | 2014 |
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| spelling | nottingham-356832020-05-04T16:59:18Z https://eprints.nottingham.ac.uk/35683/ A role for the sodium pump in H2O2-induced vasorelaxation in porcine isolated coronary arteries Wong, P.S. Garle, M.J. Alexander, S.P.H. Randall, M.D. Roberts, R.E. Hydrogen peroxide (H2O2) has been proposed to act as a factor for endothelium-derived hyperpolar-ization (EDH) and EDH may act as a ‘back up’ system to compensate the loss of the NO pathway. Here,the mechanism of action of H2O2in porcine isolated coronary arteries (PCAs) was investigated. DistalPCAs were mounted in a wire myograph and pre-contracted with U46619 (1 nM–50 muM), a throm-boxane A2-mimetic or KCl (60 mM). Concentration–response curves to H2O2(1 muM–1 mM), bradykinin(0.01 nM–1 muM), sodium nitroprusside (SNP) (10 nM–10 muM), verapamil (1 nM–10 muM), KCl (0–20 mM)or Ca2+-reintroduction (1 muM–10 mM) were constructed in the presence of various inhibitors. Activityof the Na+/K+-pump was measured through rubidium-uptake using atomic absorption spectropho-tometry. H2O2caused concentration-dependent vasorelaxations with a maximum relaxation (Rmax) of100 ± 16% (mean ± SEM), pEC50= 4.18 ± 0.20 (n = 4) which were significantly inhibited by PEG-catalase at0.1–1.0 mM H2O2(P < 0.05). 10 mM TEA significantly inhibited the relaxation up to 100 muM H2O2(P < 0.05).60 mM K+and 500 nM ouabain significantly inhibited H2O2-induced vasorelaxation producing a relax-ation of 40.8 ± 8.5% (n = 5) and 47.5 ± 8.6% (n = 6) respectively at 1 mM H2O2(P < 0.0001). H2O2-inducedvasorelaxation was unaffected by the removal of endothelium, inhibition of NO, cyclo-oxygenase, gapjunctions, SKCa, IKCa, BKCaKir, KV, KATPor cGMP. 100 muM H2O2had no effects on the KCl-induced vasore-laxation or Ca2+-reintroduction contraction. 1 mM H2O2inhibited both KCl-induced vasorelaxation andrubidium-uptake consistent with inhibition of the Na+/K+-pump activity. We have shown that the vas-cular actions of H2O2are sensitive to ouabain and high concentrations of H2O2are able to modulate theNa+/K+-pump. This may contribute towards its vascular actions. Elsevier 2014-12-03 Article PeerReviewed Wong, P.S., Garle, M.J., Alexander, S.P.H., Randall, M.D. and Roberts, R.E. (2014) A role for the sodium pump in H2O2-induced vasorelaxation in porcine isolated coronary arteries. Pharmacological Research, 90 . pp. 25-35. ISSN 1043-6618 Hydrogen peroxide (H2O2) relaxation; Ouabain-sensitive sodium–potassium pump; KCl relaxation; Rubidium uptake; Ca2+-reintroduction; Porcine coronary artery http://www.sciencedirect.com/science/article/pii/S1043661814001480 doi:10.1016/j.phrs.2014.09.004 doi:10.1016/j.phrs.2014.09.004 |
| spellingShingle | Hydrogen peroxide (H2O2) relaxation; Ouabain-sensitive sodium–potassium pump; KCl relaxation; Rubidium uptake; Ca2+-reintroduction; Porcine coronary artery Wong, P.S. Garle, M.J. Alexander, S.P.H. Randall, M.D. Roberts, R.E. A role for the sodium pump in H2O2-induced vasorelaxation in porcine isolated coronary arteries |
| title | A role for the sodium pump in H2O2-induced vasorelaxation in porcine isolated coronary arteries |
| title_full | A role for the sodium pump in H2O2-induced vasorelaxation in porcine isolated coronary arteries |
| title_fullStr | A role for the sodium pump in H2O2-induced vasorelaxation in porcine isolated coronary arteries |
| title_full_unstemmed | A role for the sodium pump in H2O2-induced vasorelaxation in porcine isolated coronary arteries |
| title_short | A role for the sodium pump in H2O2-induced vasorelaxation in porcine isolated coronary arteries |
| title_sort | role for the sodium pump in h2o2-induced vasorelaxation in porcine isolated coronary arteries |
| topic | Hydrogen peroxide (H2O2) relaxation; Ouabain-sensitive sodium–potassium pump; KCl relaxation; Rubidium uptake; Ca2+-reintroduction; Porcine coronary artery |
| url | https://eprints.nottingham.ac.uk/35683/ https://eprints.nottingham.ac.uk/35683/ https://eprints.nottingham.ac.uk/35683/ |