Increased dietary sodium inhibits baroreflex-induced bradycardia during acute sodium loading.
Increased dietary sodium inhibits baroreflex-induced bradycardia during acute sodium loading.
复制标题
增加膳食钠可抑制急性钠负荷期间压力感受反射引起的心动过缓。
DOI：
10.1152/ajpregu.00244.2004
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发表时间：
2005
期刊：
影响因子：
--
通讯作者：
Bealer,StevenL
中科院分区：
文献类型：
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作者：
Bealer,StevenL
本研究探讨了增加膳食钠对急性钠负荷引起的心脏压力感受性反射的影响。在清醒的雄性Sprague-Dawley大鼠中，仅饮用自来水（Tap）或等渗盐水（Iso）2-3周，使用四参数S形逻辑函数比较了0.6或1.0 M NaCl输注30 min之前和之后静脉注射苯肾上腺素和硝普钠期间血压和心率的变化。在Tap动物中，输注1.0 M NaCl增加了压力反射诱导的心率最小值，降低了心率范围，并增加了工作血压。在 相反，Tap大鼠输注0.6 M NaCl可降低最小和最大心率。然而，输注0.6 M NaCl的ISO动物产生的反应类似于Tap大鼠输注1.0 M NaCl。此外，Tap大鼠输注0.6 M NaCl后的最低心率降低可通过静脉注射加压素V1受体拮抗剂来预防。此外，心脏副交感神经反应是相似的，在Tap和ISO大鼠之前和之后的0.6 M NaCl输液。然而，在接受静脉注射阿托品的动物中，0.6 M NaCl降低了Tap的最小和最大心率，但未改变Iso大鼠的反应参数。这些结果表明，促进心脏压力感受器反射反应，通常观察到在中度钠负荷是由血管加压素介导的，增加膳食钠摄入逆转这种促进减少交感神经系统撤退。
The present study investigated the effects of increased dietary sodium on the modification of cardiac baroreflex responses induced by acute sodium loading. Changes in blood pressure and heart rate during intravenous phenylephrine and nitroprusside administration were compared using a four-parameter sigmoid logistic function before and after a 30-min infusion of 0.6 or 1.0 M NaCl in conscious male Sprague-Dawley rats consuming only tap water (Tap) or isotonic saline (Iso) for 2–3 wk. In Tap animals, infusion of 1.0 M NaCl increased the baroreflex-induced heart rate minimum, reduced heart rate range, and increased the operating blood pressure. In contrast, infusion of 0.6 M NaCl in Tap rats reduced both heart rate minimum and maximum. However, infusion of 0.6 M NaCl in Iso animals produced responses similar to that shown in Tap rats infused with 1.0 M NaCl. In addition, the decreased heart rate minimum in Tap rats after infusion of 0.6 M NaCl was prevented by intravenous administration of a vasopressin V1-receptor antagonist. Furthermore, cardiac parasympathetic responses were similar in Tap and Iso rats before and after 0.6 M NaCl infusion. However, in animals receiving intravenous atropine, 0.6 M NaCl decreased heart rate minimum and maximum in Tap but did not alter the response parameters in Iso rats. These results demonstrate that the facilitation of cardiac baroreflex responses normally observed during moderate sodium loading is mediated by vasopressin and that increased dietary sodium ingestion reverses this facilitation by reducing sympathetic nervous system withdrawal.