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Vasoconstriction triggered by hydrogen sulfide: Evidence for Na+,K+,2Cl-cotransport and L-type Ca2+ channel-mediated pathway.

ABSTRACT: This study examined the dose-dependent actions of hydrogen sulfide donor sodium hydrosulphide (NaHS) on isometric contractions and ion transport in rat aorta smooth muscle cells (SMC).Isometric contraction was measured in ring aortas segments from male Wistar rats. Activity of Na+/K+-pump and Na+,K+,2Cl-cotransport was measured in cultured endothelial and smooth muscle cells from the rat aorta as ouabain-sensitive and ouabain-resistant, bumetanide-sensitive components of the 86Rb influx, respectively.NaHS exhibited the bimodal action on contractions triggered by modest depolarization ([K+]o=30 mM). At 10-4 M, NaHS augmented contractions of intact and endothelium-denuded strips by ~ 15% and 25%, respectively, whereas at concentration of 10-3 M it decreased contractile responses by more than two-fold. Contractions evoked by 10-4 M NaHS were completely abolished by bumetanide, a potent inhibitor of Na+,K+,2Cl-cotransport, whereas the inhibition seen at 10-3 M NaHS was suppressed in the presence of K+ channel blocker TEA. In cultured SMC, 5×10-5 M NaHS increased Na+,K+,2Cl- - cotransport without any effect on the activity of this carrier in endothelial cells. In depolarized SMC, 45Ca influx was enhanced in the presence of 10-4 M NaHS and suppressed under elevation of [NaHS] up to 10-3 M. 45Ca influx triggered by 10-4 M NaHS was abolished by bumetanide and L-type Ca2+ channel blocker nicardipine.Our results strongly suggest that contractions of rat aortic rings triggered by low doses of NaHS are mediated by activation of Na+,K+,2Cl-cotransport and Ca2+ influx via L-type channels.

SUBMITTER: Orlov SN

PROVIDER: S-EPMC5683885 | biostudies-other | 2017 Dec

REPOSITORIES: biostudies-other

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Vasoconstriction triggered by hydrogen sulfide: Evidence for Na<sup>+</sup>,K<sup>+</sup>,2Cl<sup>-</sup>cotransport and L-type Ca<sup>2+</sup> channel-mediated pathway.

Orlov Sergei N SN Gusakova Svetlana V SV Smaglii Liudmila V LV Koltsova Svetlana V SV Sidorenko Svetalana V SV

Biochemistry and biophysics reports 20171106

<h4>Objectives</h4>This study examined the dose-dependent actions of hydrogen sulfide donor sodium hydrosulphide (NaHS) on isometric contractions and ion transport in rat aorta smooth muscle cells (SMC).<h4>Methods</h4>Isometric contraction was measured in ring aortas segments from male Wistar rats. Activity of Na<sup>+</sup>/K<sup>+</sup>-pump and Na<sup>+</sup>,K<sup>+</sup>,2Cl<sup>-</sup>cotransport was measured in cultured endothelial and smooth muscle cells from the rat aorta as ouabain-se ...[more]

PMID: 29159314

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Project description:Mice with smooth muscle (SM)-specific knockout of Na(+)/Ca(2+) exchanger type-1 (NCX1(SM-/-)) and the NCX inhibitor, SEA0400, were used to study the physiological role of NCX1 in mouse mesenteric arteries. NCX1 protein expression was greatly reduced in arteries from NCX1(SM-/-) mice generated with Cre recombinase. Mean blood pressure (BP) was 6-10 mmHg lower in NCX1(SM-/-) mice than in wild-type (WT) controls. Vasoconstriction was studied in isolated, pressurized mesenteric small arteries from WT and NCX1(SM-/-) mice and in heterozygotes with a global null mutation (NCX1(Fx/-)). Reduced NCX1 activity was manifested by a marked attenuation of responses to low extracellular Na(+) concentration, nanomolar ouabain, and SEA0400. Myogenic tone (MT, 70 mmHg) was reduced by approximately 15% in NCX1(SM-/-) arteries and, to a similar extent, by SEA0400 in WT arteries. MT was normal in arteries from NCX1(Fx/-) mice, which had normal BP. Vasoconstrictions to phenylephrine and elevated extracellular K(+) concentration were significantly reduced in NCX1(SM-/-) arteries. Because a high extracellular K(+) concentration-induced vasoconstriction involves the activation of L-type voltage-gated Ca(2+) channels (LVGCs), we measured LVGC-mediated currents and Ca(2+) sparklets in isolated mesenteric artery myocytes. Both the currents and the sparklets were significantly reduced in NCX1(SM-/-) (vs. WT or NCX1(Fx/-)) myocytes, but the voltage-dependent inactivation of LVGCs was not augmented. An acute application of SEA0400 in WT myocytes had no effect on LVGC current. The LVGC agonist, Bay K 8644, eliminated the differences in LVGC currents and Ca(2+) sparklets between NCX1(SM-/-) and control myocytes, suggesting that LVGC expression was normal in NCX1(SM-/-) myocytes. Bay K 8644 did not, however, eliminate the difference in myogenic constriction between WT and NCX1(SM-/-) arteries. We conclude that, under physiological conditions, NCX1-mediated Ca(2+) entry contributes significantly to the maintenance of MT. In NCX1(SM-/-) mouse artery myocytes, the reduced Ca(2+) entry via NCX1 may lower cytosolic Ca(2+) concentration and thereby reduce MT and BP. The reduced LVGC activity may be the consequence of a low cytosolic Ca(2+) concentration.

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Dataset Information

Vasoconstriction triggered by hydrogen sulfide: Evidence for Na+,K+,2Cl-cotransport and L-type Ca2+ channel-mediated pathway.

Publications

Vasoconstriction triggered by hydrogen sulfide: Evidence for Na<sup>+</sup>,K<sup>+</sup>,2Cl<sup>-</sup>cotransport and L-type Ca<sup>2+</sup> channel-mediated pathway.

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