血管紧张素 AT1 受体阻断对健康男性握力时交感神经反应的影响。

Effect of angiotensin AT1 receptor blockade on sympathetic responses to handgrip in healthy men.

机构信息

University Health Network, Mount Sinai Hospital, Division of Cardiology, Department of Medicine, University of Toronto, Ontario, Canada.

出版信息

Am J Hypertens. 2011 May;24(5):537-43. doi: 10.1038/ajh.2011.14. Epub 2011 Feb 17.

DOI:10.1038/ajh.2011.14

PMID:21331055

Abstract

BACKGROUND

To determine whether angiotensin II (ANG II) contributes to the reflex skeletal muscle sympathoexcitation elicited by isometric and isotonic exercise, we tested the hypothesis that angiotensin AT(1) receptor blockade (ARB) would attenuate reflex sympathoneural responses to handgrip (HG) and to post-handgrip ischemia (PHGI).

METHODS

Seventeen healthy men were studied before and 1 week after random double-blind crossover allocation to oral losartan (100 mg daily) and placebo. Heart rate (HR), blood pressure (BP), and muscle sympathetic nerve activity (MSNA) were recorded at rest, and during 2 min bouts of isotonic HG at 50% maximum voluntary contraction (MVC) and isometric HG at 30% MVC, performed randomly, each followed by 2 min of PHGI.

RESULTS

At rest, losartan doubled plasma renin (P = 0.01) and ANG II (P = 0.03) concentrations, and lowered BP (P < 0.01) yet had no effect on MSNA burst frequency or incidence. HR trended higher (P = 0.060). Losartan's hypotensive effect persisted throughout each exercise bout (P < 0.045). MSNA and HR responses to isotonic exercise and postexercise ischemia were not affected by losartan. Isometric exercise and postexercise ischemia increased MSNA on both sessions (all P < 0.01). Losartan augmented the HR response (P ≤ 0.03), and after losartan MSNA burst frequency (P < 0.01) and incidence (P < 0.04) were significantly higher at all time points, but the magnitude of the MSNA response to isometric exercise and postexercise ischemia was unchanged.

CONCLUSION

In healthy men, short-term ARB does not attenuate reflex sympathoneural responses to HG or PHGI.

摘要

背景

为了确定血管紧张素 II（ANG II）是否导致等长和等张运动引起的反射性骨骼肌交感兴奋，我们检验了血管紧张素 AT（1）受体阻断（ARB）会减弱握力（HG）和握力后缺血（PHGI）反射性交感神经反应的假说。

方法

17 名健康男性在随机双盲交叉分配口服氯沙坦（100mg 每日）和安慰剂之前和之后一周进行研究。在休息时、以 50%最大自主收缩（MVC）进行 2 分钟的等张 HG 以及以 30% MVC 进行 2 分钟的等长 HG 期间记录心率（HR）、血压（BP）和肌肉交感神经活动（MSNA）。

结果

在休息时，氯沙坦使血浆肾素（P = 0.01）和 ANG II（P = 0.03）浓度增加一倍，降低血压（P < 0.01），但对 MSNA 爆发频率或发生率没有影响。HR 趋势升高（P = 0.060）。氯沙坦的降压作用在每次运动过程中持续存在（P < 0.045）。MSNA 和 HR 对等张运动和运动后缺血的反应不受氯沙坦影响。等长运动和运动后缺血在两次运动中均增加了 MSNA（均 P < 0.01）。氯沙坦增强了 HR 反应（P ≤ 0.03），并且在氯沙坦后，MSNA 爆发频率（P < 0.01）和发生率（P < 0.04）在所有时间点均显着升高，但等长运动和运动后缺血的 MSNA 反应幅度保持不变。