Dietary nitrate increases tetanic [Ca2+]i and contractile force in mouse fast-twitch muscle
Dietary nitrate increases tetanic [Ca2+]i and contractile force in mouse fast-twitch muscle
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DOI：
10.1113/jphysiol.2012.232777
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发表时间：
2012-08-01
影响因子：
5.5
通讯作者：
Westerblad, Hakan
中科院分区：
文献类型：
--
作者：
Hernandez, Andres;Schiffer, Tomas A.;Westerblad, Hakan
膳食无机硝酸盐对健康和运动的生理反应具有深远的影响。在这里，我们使用 C57bl/6 雄性小鼠的快肌和慢肌骨骼肌，在正常饮食中容易达到的剂量下，检查硝酸盐是否可以改善 Ca2+ 处理和收缩功能，这些小鼠被给予 1 毫米硝酸钠水溶液 7 天。向年龄匹配的对照提供不添加硝酸盐的水。在从硝酸盐处理的小鼠中解剖的快肌纤维中，在 20 至 150 Hz 的刺激频率下，肌浆游离 [Ca2+] 显着高于对照纤维，这导致在 = 50 Hz 时收缩力显着增加。在 100 Hz 刺激下，硝酸盐组的力量发展速度快了 35%。硝酸盐治疗小鼠的这些变化伴随着 Ca2+ 处理蛋白 calsequestrin 1 和二氢吡啶受体表达的增加。在慢肌中未测量到力或 calsequestrin 1 和二氢吡啶受体表达的变化。总之，这些结果表明补充硝酸盐对快肌中细胞内 Ca2+ 处理具有显着影响，从而导致力量产生增加。揭示了一种新机制，硝酸盐可以通过该机制对肌肉功能产生影响，并应用于运动表现和对肌肉无力的潜在治疗作用。
Dietary inorganic nitrate has profound effects on health and physiological responses to exercise. Here, we examined if nitrate, in doses readily achievable via a normal diet, could improve Ca2+ handling and contractile function using fast- and slow-twitch skeletal muscles from C57bl/6 male mice given 1 mm sodium nitrate in water for 7 days. Age matched controls were provided water without added nitrate. In fast-twitch muscle fibres dissected from nitrate treated mice, myoplasmic free [Ca2+] was significantly greater than in Control fibres at stimulation frequencies from 20 to 150 Hz, which resulted in a major increase in contractile force at =50 Hz. At 100 Hz stimulation, the rate of force development was 35% faster in the nitrate group. These changes in nitrate treated mice were accompanied by increased expression of the Ca2+ handling proteins calsequestrin 1 and the dihydropyridine receptor. No changes in force or calsequestrin 1 and dihydropyridine receptor expression were measured in slow-twitch muscles. In conclusion, these results show a striking effect of nitrate supplementation on intracellular Ca2+ handling in fast-twitch muscle resulting in increased force production. A new mechanism is revealed by which nitrate can exert effects on muscle function with applications to performance and a potential therapeutic role in conditions with muscle weakness.