运动可揭示近期发生心肌梗死的猪的自主神经功能障碍。

Exercise unmasks autonomic dysfunction in swine with a recent myocardial infarction.

作者信息

Duncker Dirk J, Haitsma David B, Liem David A, Verdouw Pieter D, Merkus Daphne

机构信息

Experimental Cardiology, Thoraxcenter, Erasmus MC, University Medical Center Rotterdam, P.O. Box 1738, 3000 DR Rotterdam, The Netherlands.

出版信息

Cardiovasc Res. 2005 Mar 1;65(4):889-96. doi: 10.1016/j.cardiores.2004.12.010.

DOI:10.1016/j.cardiores.2004.12.010

PMID:15721869

Abstract

OBJECTIVE

Severe congestive heart failure is associated with autonomic imbalance consisting of an increased sympathetic and decreased parasympathetic activity. In the present study, we investigated the influence of alterations in autonomic balance on cardiovascular function in 11 swine with left ventricular (LV) dysfunction produced by a 2- to 3-week-old myocardial infarction (MI).

METHODS

Swine underwent permanent occlusion of the left circumflex coronary artery resulting in MI of the lateral LV wall. Autonomic activity was studied 2-3 weeks later using blockers of muscarinic (atropine), alpha-adrenergic (phentolamine) and beta-adrenergic (propranolol) receptors.

RESULTS

Under resting conditions, parasympathetic and sympathetic control of the heart and coronary circulation were similar in MI and normal swine. In contrast, during exercise of MI compared to normal swine, (i) there was a more pronounced gradual inhibition of parasympathetic control of heart rate with increasing exercise intensity; (ii) circulating catecholamines increased excessively, resulting in an increased beta-adrenergic influence on heart rate, while (iii) the beta-adrenergic influence on global left ventricular contractility was decreased, reflecting a blunted left ventricular beta-adrenergic responsiveness. Furthermore, (iv) an alpha-adrenergic vasoconstrictor influence was absent in the anterior LV wall of both MI and normal swine, while (v) the beta-adrenergic vasodilator influence in the coronary circulation was not different between normal and MI swine, which, in conjunction with the elevated catecholamine levels during exercise, suggests a diminished beta-adrenergic responsiveness of coronary resistance vessels within remote non-infarcted myocardium in MI swine.

CONCLUSIONS

Swine with a recent MI display autonomic dysfunction, which is characterized by a more pronounced inhibition of parasympathetic influence and an exaggerated increase in sympathetic drive during exercise, as well as reduced myocardial and coronary vascular beta-adrenergic responsiveness.

摘要

目的

严重充血性心力衰竭与自主神经失衡有关，表现为交感神经活动增强和副交感神经活动减弱。在本研究中，我们调查了11只因2至3周前心肌梗死（MI）导致左心室（LV）功能障碍的猪自主神经平衡改变对心血管功能的影响。

方法

猪接受左旋冠状动脉永久闭塞，导致左心室侧壁心肌梗死。2至3周后，使用毒蕈碱（阿托品）、α-肾上腺素能（酚妥拉明）和β-肾上腺素能（普萘洛尔）受体阻滞剂研究自主神经活动。

结果

在静息状态下，心肌梗死猪和正常猪对心脏和冠状动脉循环的副交感神经和交感神经控制相似。相比之下，与正常猪相比，心肌梗死猪在运动期间，（i）随着运动强度增加，对心率的副交感神经控制逐渐受到更明显的抑制；（ii）循环儿茶酚胺过度增加，导致β-肾上腺素能对心率的影响增加，而（iii）β-肾上腺素能对整体左心室收缩力的影响降低，反映出左心室β-肾上腺素能反应迟钝。此外，（iv）心肌梗死猪和正常猪的左心室前壁均不存在α-肾上腺素能血管收缩作用，而（v）正常猪和心肌梗死猪冠状动脉循环中的β-肾上腺素能血管舒张作用无差异，这与运动期间儿茶酚胺水平升高相结合，表明心肌梗死猪远隔非梗死心肌内冠状动脉阻力血管的β-肾上腺素能反应性降低。