Effects of dietary sodium restriction on heart rate control in rats.
Effects of dietary sodium restriction on heart rate control in rats.
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饮食钠限制对大鼠心率控制的影响。
DOI：
10.1152/ajpregu.1983.244.2.r264
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发表时间：
1983
期刊：
影响因子：
--
通讯作者：
Vollmer,RR
中科院分区：
文献类型：
--
作者：
Bush,EN;Vollmer,RR
在雄性Wistar大鼠中评价饮食钠限制对心率控制的影响，所述雄性Wistar大鼠维持低钠饮食（22 meq/kg饮食）或标准钠饮食（141 meq/kg饮食）4周。在清醒的低钠大鼠中，阿托品引起的心率增加大于标准钠动物，表明基础副交感神经张力升高。钠限制不影响基础交感神经紧张，因为在两个饮食组中普萘洛尔产生了相似的心率降低。然而，交感神经介导的心动过速反应硝普钠增强低钠大鼠。这种增强交感神经功能也观察到低钠动物脊髓后。脊髓交感神经刺激产生的心率增加显着加剧，而对去甲肾上腺素的反应不受饮食的影响。这一发现与异丙肾上腺素引起的离体心房变时性反应不改变的观察结果一致。当神经元对心率的影响被阻断阿托品和普萘洛尔或氯异达明在清醒大鼠联合给药，潜在的固有心率被发现在低钠大鼠显着较高。总之，本研究确定了钠限制对大鼠心率控制的三种影响：1）基础副交感神经张力增加，2）交感神经激活的心率反应增强，3）固有心率升高。
The effects of dietary sodium restriction on heart rate control were evaluated in male Wistar rats maintained for 4 wk on a low- (22 meq/kg diet) or standard (141 meq/kg diet) sodium diet. In conscious low-sodium rats, atropine produced heart rate increases greater than in standard sodium animals, indicating that basal parasympathetic tone was elevated. Sodium restriction did not affect basal sympathetic tone, since similar reductions in heart rate were produced by propranolol in both dietary groups. However, sympathetically mediated tachycardic responses to sodium nitroprusside were augmented in low-sodium rats. This enhancement of sympathetic function was also observed in low-sodium animals after pithing. The increases in heart rate produced by spinal sympathetic stimulation were significantly accentuated; whereas, responses to norepinephrine were not affected by the diets. This finding is in agreement with the observation that the chronotropic responses elicited by isoproterenol in isolated atria were not altered. When neuronal influences on heart rate were blocked by combined administration of atropine and propranolol or chlorisondamine in conscious rats, the underlying intrinsic cardiac rate was found to be significantly higher in low-sodium rats. In summary, the present study identifies three effects of sodium restriction on heart rate control in the rat: 1) basal parasympathetic tone is increased, 2) heart rate responses to sympathetic activation are enhanced, and 3) the intrinsic cardiac rate is elevated.