The role of extracellular signal-regulated kinase in beta-adrenoceptor-mediated vasodilatation

Beta-Adrenoceptors (B-ARs) mediate vasodilatation by activating various mechanisms that collectively contribute to vascular smooth muscle (VSM) relaxation. It has been shown that B2-AR stimulation in cultured cells results in activation of extracellular signal-regulated kinase (ERK). As the function...

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Main Author: Uhiara, Chukwuemeka Obinna
Format: Thesis (University of Nottingham only)
Language:English
Published: 2012
Subjects:
Online Access:https://eprints.nottingham.ac.uk/12695/
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author Uhiara, Chukwuemeka Obinna
author_facet Uhiara, Chukwuemeka Obinna
author_sort Uhiara, Chukwuemeka Obinna
building Nottingham Research Data Repository
collection Online Access
description Beta-Adrenoceptors (B-ARs) mediate vasodilatation by activating various mechanisms that collectively contribute to vascular smooth muscle (VSM) relaxation. It has been shown that B2-AR stimulation in cultured cells results in activation of extracellular signal-regulated kinase (ERK). As the functional relevance of this was not known, the aim of the current investigation was determine the role of ERK in beta-AR-mediated vasodilatation. Isoprenaline-induced relaxation of porcine coronary artery (PCA) segments pre-contracted with the thromboxane mimetic U46619 was significantly enhanced by inhibition of ERK activation. Relaxations to the beta2-AR agonist salbutamol, but not those to the beta1-AR agonist xamoterol or the adenylyl cyclase activator forskolin, were also enhanced. The intermediate-conductance Ca2+-activated K+ (IKCa) channel blocker TRAM-34 prevented the enhancement of beta2-AR-mediated responses. Taken together, the data indicate that ERK inhibits beta2-AR-mediated vasodilatation by interacting with a cyclic 3’, 5’-adenosine monophosphate-independent relaxation pathway involving K+ channels. This may occur through a direct regulatory action on the IKCa channel via phosphorylation. Furthermore, the finding that increased ERK activation in a rat model of Type II diabetes was associated with significantly impaired beta-AR-mediated vasodilatation raises the possibility that ERK may represent a promising therapeutic target in the treatment of disease states characterised by abnormal vascular function.
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format Thesis (University of Nottingham only)
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spelling nottingham-126952025-02-28T11:20:50Z https://eprints.nottingham.ac.uk/12695/ The role of extracellular signal-regulated kinase in beta-adrenoceptor-mediated vasodilatation Uhiara, Chukwuemeka Obinna Beta-Adrenoceptors (B-ARs) mediate vasodilatation by activating various mechanisms that collectively contribute to vascular smooth muscle (VSM) relaxation. It has been shown that B2-AR stimulation in cultured cells results in activation of extracellular signal-regulated kinase (ERK). As the functional relevance of this was not known, the aim of the current investigation was determine the role of ERK in beta-AR-mediated vasodilatation. Isoprenaline-induced relaxation of porcine coronary artery (PCA) segments pre-contracted with the thromboxane mimetic U46619 was significantly enhanced by inhibition of ERK activation. Relaxations to the beta2-AR agonist salbutamol, but not those to the beta1-AR agonist xamoterol or the adenylyl cyclase activator forskolin, were also enhanced. The intermediate-conductance Ca2+-activated K+ (IKCa) channel blocker TRAM-34 prevented the enhancement of beta2-AR-mediated responses. Taken together, the data indicate that ERK inhibits beta2-AR-mediated vasodilatation by interacting with a cyclic 3’, 5’-adenosine monophosphate-independent relaxation pathway involving K+ channels. This may occur through a direct regulatory action on the IKCa channel via phosphorylation. Furthermore, the finding that increased ERK activation in a rat model of Type II diabetes was associated with significantly impaired beta-AR-mediated vasodilatation raises the possibility that ERK may represent a promising therapeutic target in the treatment of disease states characterised by abnormal vascular function. 2012-07-19 Thesis (University of Nottingham only) NonPeerReviewed application/pdf en arr https://eprints.nottingham.ac.uk/12695/1/Thesis_FINAL.pdf Uhiara, Chukwuemeka Obinna (2012) The role of extracellular signal-regulated kinase in beta-adrenoceptor-mediated vasodilatation. PhD thesis, University of Nottingham. ERK B-adrenoceptors porcine coronary artery statins
spellingShingle ERK
B-adrenoceptors
porcine coronary artery
statins
Uhiara, Chukwuemeka Obinna
The role of extracellular signal-regulated kinase in beta-adrenoceptor-mediated vasodilatation
title The role of extracellular signal-regulated kinase in beta-adrenoceptor-mediated vasodilatation
title_full The role of extracellular signal-regulated kinase in beta-adrenoceptor-mediated vasodilatation
title_fullStr The role of extracellular signal-regulated kinase in beta-adrenoceptor-mediated vasodilatation
title_full_unstemmed The role of extracellular signal-regulated kinase in beta-adrenoceptor-mediated vasodilatation
title_short The role of extracellular signal-regulated kinase in beta-adrenoceptor-mediated vasodilatation
title_sort role of extracellular signal-regulated kinase in beta-adrenoceptor-mediated vasodilatation
topic ERK
B-adrenoceptors
porcine coronary artery
statins
url https://eprints.nottingham.ac.uk/12695/