Dietary salt intake alters cardiovascular responses evoked from the rostral ventrolateral medulla
Dietary salt intake alters cardiovascular responses evoked from the rostral ventrolateral medulla
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DOI：
10.1152/ajpregu.1999.276.6.r1600
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发表时间：
1999-06-01
影响因子：
2.8
通讯作者：
Sved, AF
中科院分区：
文献类型：
--
作者：
Ito, S;Gordon, FJ;Sved, AF
本实验研究是否在大鼠食用高NaCl含量（8%）或低Na+含量（0.01%）的饮食2周的兴奋性输入到延髓头端腹外侧（RVLM）将被改变。在氯醛糖麻醉的大鼠，谷氨酸注射到RVLM引起的压力反应，与对照饮食喂养的大鼠相比，是50%以上的大鼠喂养的饮食含有8%的NaCl和25%以下的大鼠喂养的饮食含有0.01%的Na+。加压反应产生的坐骨神经传入的电刺激，以及通过微量注射到RVLM的L-二羟基苯丙氨酸或卡巴胆碱，都增强了高饮食中的盐摄入量和低饮食中的盐摄入量减少。饮食中的盐摄入量没有影响加压反应产生的静脉注射苯肾上腺素，表明盐相关的改变，在心血管反应产生的中枢激活不能占外周血管反应性的变化。谷氨酸注射到孤束核产生的动脉压的降低也增强了高盐饮食，这表明中枢压力感受器反射途径的敏感性可能会改变饮食NaCl。这些结果表明，在饮食中消耗的NaCl的量可以改变RVLM交感神经元的敏感性，这种敏感性的变化不限于任何特定类别的细胞表面受体。
The present experiments examined whether in rats consuming diets with either high NaCl content (8%) or low Na+ content (0.01%) for 2 wk excitatory inputs to the rostral ventrolateral medulla (RVLM) would be altered. In chloralose-anesthetized rats, injection of glutamate into the RVLM elicited a presser response that, compared with rats fed a control diet, was 50% larger in rats fed a diet containing 8% NaCl and was 25% smaller in rats fed a diet containing 0.01% Na+. Presser responses produced by electrical stimulation of sciatic nerve afferents, as well as by microinjections into the RVLM of L-dihydroxyphenylalanine or carbachol, were all potentiated by high dietary salt intake and reduced by low dietary salt intake. Dietary salt intake had no effect on presser responses produced by intravenous injection of phenylephrine, indicating that salt-related alterations in cardiovascular responses produced by central activation could not be accounted for by changes in peripheral vascular reactivity. The decrease in arterial pressure produced by injection of glutamate into the nucleus of the solitary tract was also potentiated by the high salt diet, suggesting that the sensitivity of central baroreceptor reflex pathways may be altered by dietary NaCl. These results indicate that the amount of NaCl consumed in the diet can change the sensitivity of RVLM sympathoexcitatory neurons, and this change in sensitivity is not restricted to any particular class of cell surface receptors.