Increase in sympathetic activity with age. I. Role of impairment of arterial baroreflexes.
Increase in sympathetic activity with age. I. Role of impairment of arterial baroreflexes.
复制标题
交感神经活动随着年龄的增长而增加。
DOI：
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发表时间：
1991
影响因子：
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通讯作者：
F. Abboud
中科院分区：
文献类型：
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作者：
G. Hajduczok;M. Chapleau;S. L. Johnson;F. Abboud
本研究的目的是评估动脉压力感受性反射功能随年龄的变化。在清醒状态下获得的年轻动物（1岁; n = 5）和老年比格犬（11岁; n = 11）的平均动脉压（MAP）分别为110 +/- 7 mmHg和128 +/- 6 mmHg（P <0.05）。在清醒状态下，静脉注射不同剂量的苯肾上腺素和硝酸甘油后，老年动物的心率（HR）与MAP相关的斜率显著低于年轻动物（-0.87 ± 0.30 vs. -2.35 ± 0.44 beats.min-1.mmHg-1; P <0.05）。阿托品后，两组HR的压力感受性反射控制均消失。在麻醉和主动脉减压神经的切片后，并且在单独的颈动脉窦压力（CSP）保持在50 mmHg的情况下，老年动物（368 +/- 40 Hz）的绝对肾交感神经活动（RSNA）显著大于年轻动物（41 +/- 9 Hz）。在老年人中，与年轻人相比，在CSP增加期间，MAP（0.78 +/- 0.09）和标准化RSNA（0.38 +/- 0.14%/mmHg）的压力感受性反射抑制增益显著降低（MAP，1.16 +/- 0.17 mmHg，RSNA，0.72 +/- 0.06%/mmHg）。在一个血压正常的老年动物亚组（n = 5）中，RSNA的压力感受性反射增益与年轻动物相比仍然减弱（0.43 ± 0.11%/mmHg）。在老年比格犬与年轻比格犬中，绝对RSNA反射减少作为基线RSNA的函数也受损。（250字处删节）
The purpose of this study was to evaluate changes in arterial baroreflex function with aging. Mean arterial pressure (MAP) obtained in the awake state was 110 +/- 7 mmHg in the young animals (1 yr; n = 5) and 128 +/- 6 mmHg in the old beagles (11 yr; n = 11) (P less than 0.05). In response to bolus administration of varying doses of phenylephrine and nitroglycerin in the conscious state, the slope relating heart rate (HR) to MAP was attenuated significantly in the old animals compared with the young (-0.87 +/- 0.30 vs. -2.35 +/- 0.44 beats.min-1.mmHg-1; P less than 0.05). After atropine, the baroreflex control of HR was abolished in both groups. After anesthesia and sectioning of the aortic depressor nerves, and with isolated carotid sinus pressures (CSP) held at 50 mmHg, absolute renal sympathetic nerve activity (RSNA) was significantly greater in the old (368 +/- 40 Hz) vs. the young animals (41 +/- 9 Hz). In the old, the gains of baroreflex inhibition of MAP (0.78 +/- 0.09) and normalized RSNA (0.38 +/- 0.14%/mmHg) during increases in CSP were decreased significantly compared with the young (MAP, 1.16 +/- 0.17 mmHg, and RSNA, 0.72 +/- 0.06%/mmHg). In a subgroup of old normotensive animals (n = 5), the baroreflex gain of RSNA was still attenuated (0.43 +/- 0.11%/mmHg) compared with the young. The reflex reduction in absolute RSNA as a function of baseline RSNA was also impaired in old vs. young beagles.(ABSTRACT TRUNCATED AT 250 WORDS)