Erschienen in:
01.05.2016 | Original Contribution
Dietary nitrate improves cardiac contractility via enhanced cellular Ca2+ signaling
verfasst von:
Gianluigi Pironti, Niklas Ivarsson, Jiangning Yang, Alex Bersellini Farinotti, William Jonsson, Shi-Jin Zhang, Duygu Bas, Camilla I. Svensson, Håkan Westerblad, Eddie Weitzberg, Jon O. Lundberg, John Pernow, Johanna Lanner, Daniel C. Andersson
Erschienen in:
Basic Research in Cardiology
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Ausgabe 3/2016
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Abstract
The inorganic anion nitrate (NO3
−), which is naturally enriched in certain vegetables (e.g., spinach and beetroot), has emerged as a dietary component that can regulate diverse bodily functions, including blood pressure, mitochondrial efficiency, and skeletal muscle force. It is not known if dietary nitrate improves cardiac contractility. To test this, mice were supplemented for 1–2 weeks with sodium nitrate in the drinking water at a dose similar to a green diet. The hearts from nitrate-treated mice showed increased left ventricular pressure and peak rate of pressure development as measured with the Langendorff heart technique. Cardiomyocytes from hearts of nitrate-treated and control animals were incubated with the fluorescent indicator Fluo-3 to measure cytoplasmic free [Ca2+] and fractional shortening. Cardiomyocytes from nitrate-treated mice displayed increased fractional shortening, which was linked to larger Ca2+ transients. Moreover, nitrate hearts displayed increased protein expression of the l-type Ca2+ channel/dihydropyridine receptor and peak l-type Ca2+ channel currents. The nitrate-treated hearts displayed increased concentration of cAMP but unchanged levels of cGMP compared with controls. These findings provide the first evidence that dietary nitrate can affect the expression of important Ca2+ handling proteins in the heart, resulting in increased cardiomyocyte Ca2+ signaling and improved left ventricular contractile function. Our observation shows that dietary nitrate impacts cardiac function and adds understanding to inorganic nitrate as a physiological modulator.