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Dexmedetomidine-Induced Contraction in the Isolated Endothelium-Denuded Rat Aorta Involves PKC-?-mediated JNK Phosphorylation.

ABSTRACT: Vasoconstriction mediated by the highly selective alpha-2 adrenoceptor agonist dexmedetomidine leads to transiently increased blood pressure and severe hypertension. The dexmedetomidine-induced contraction involves the protein kinase C (PKC)-mediated pathway. However, the main PKC isoform involved in the dexmedetomidine-induced contraction remains unknown. The goal of this in vitro study was to examine the specific PKC isoform that contributes to the dexmedetomidine-induced contraction in the isolated rat aorta. The endothelium-denuded rat aorta was suspended for isometric tension recording. Dexmedetomidine dose-response curves were generated in the presence or absence of the following inhibitors: the pan-PKC inhibitor, chelerythrine; the PKC-? and -? inhibitor, Go6976; the PKC-? inhibitor, safingol; the PKC-? inhibitor, ruboxistaurin; the PKC-? inhibitor, rottlerin; the c-Jun NH2-terminal kinase (JNK) inhibitor, SP600125; and the myosin light chain kinase inhibitor, ML-7 hydrochloride. Western blot analysis was used to examine the effect of rottlerin on dexmedetomidine-induced PKC-? expression and JNK phosphorylation in rat aortic vascular smooth muscle cells (VSMCs) and to investigate the effect of dexmedetomidine on PKC-? expression in VSMCs transfected with PKC-? small interfering RNA (siRNA) or control siRNA. Chelerythrine as well as SP600125 and ML-7 hydrochloride attenuated the dexmedetomidine-induced contraction. Go6976, safingol, and ruboxistaurin had no effect on the dexmedetomidine-induced contraction, whereas rottlerin inhibited the dexmedetomidine-induced contraction. Dexmedetomidine induced PKC-? expression, whereas rottlerin and PKC-? siRNA transfection inhibited dexmedetomidine-induced PKC-? expression. Dexmedetomidine also induced JNK phosphorylation, which was inhibited by rottlerin. Taken together, these results suggest that the dexmedetomidine-induced contraction involves PKC-?-dependent JNK phosphorylation in the isolated rat aorta.

SUBMITTER: Yu J

PROVIDER: S-EPMC4571550 | biostudies-literature | 2015

REPOSITORIES: biostudies-literature

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Dexmedetomidine-Induced Contraction in the Isolated Endothelium-Denuded Rat Aorta Involves PKC-δ-mediated JNK Phosphorylation.

Yu Jongsun J Ok Seong-Ho SH Kim Won Ho WH Cho Hyunhoo H Park Jungchul J Shin Il-Woo IW Lee Heon Keun HK Chung Young-Kyun YK Choi Mun-Jeoung MJ Kwon Seong-Chun SC Sohn Ju-Tae JT

International journal of medical sciences 20150904 9

Vasoconstriction mediated by the highly selective alpha-2 adrenoceptor agonist dexmedetomidine leads to transiently increased blood pressure and severe hypertension. The dexmedetomidine-induced contraction involves the protein kinase C (PKC)-mediated pathway. However, the main PKC isoform involved in the dexmedetomidine-induced contraction remains unknown. The goal of this in vitro study was to examine the specific PKC isoform that contributes to the dexmedetomidine-induced contraction in the is ...[more]

PMID: 26392810

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Project description:Gut microbiota are emerging as potential contributors to the regulation of host homeostasis. Dysbiosis of the gut microbiota associated with increased intestinal permeability facilitates the passage of endotoxins and other microbial products, including indoxyl sulfate in the circulation. Although an emerging body of evidence has suggested that indoxyl sulfate is a key substance for the development of chronic kidney disease, few studies have investigated the direct association of indoxyl sulfate with vascular function. We hypothesized that indoxyl sulfate adversely affects vascular function. Aortas isolated from male Wistar rat were examined in the presence or absence of indoxyl sulfate to assess the vascular function, including vasorelaxation and vasocontraction. Indoxyl sulfate (vs. vehicle) (1) decreased vasorelaxation induced by acetylcholine (ACh) but not by sodium nitroprusside; (2) had no significant alterations of noradrenaline-induced vasocontraction in the absence and presence of endothelium; (3) decreased adenylyl cyclase activator (forskolin)-induced vasorelaxation, while such a difference was eliminated by endothelial denudation; and (4) decreased vasorelaxations induced by calcium ionophore (A23187) and transient receptor potential vanilloid 4 agonist (GSK1016790A). The indoxyl sulfate-induced decrease in the vasorelaxations induced by ACh and A23187 increased by cell-permeant superoxide dismutase or by organic anion transporter inhibitor. However, apocynin, an inhibitor of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, had no effects on vasorelaxations induced by ACh, A23187, forskolin, and GSK1016790A in the presence of indoxyl sulfate. These results suggest that indoxyl sulfate directly affects the vascular function, particularly, endothelium-dependent vasorelaxation, and this effect may be attributable to increased oxidative stress after cell transportion via organic anion transporter, and such increased oxidative stress may not be attributable to activation of NADPH oxidase activation.

Dataset Information

Dexmedetomidine-Induced Contraction in the Isolated Endothelium-Denuded Rat Aorta Involves PKC-?-mediated JNK Phosphorylation.

Publications

Dexmedetomidine-Induced Contraction in the Isolated Endothelium-Denuded Rat Aorta Involves PKC-δ-mediated JNK Phosphorylation.

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