beta-adrenergic receptor signaling: an acute compensatory adjustment-inappropriate for the chronic stress of heart failure? Insights from Gsalpha overexpression and other genetically engineered animal models.
beta-adrenergic receptor signaling: an acute compensatory adjustment-inappropriate for the chronic stress of heart failure? Insights from Gsalpha overexpression and other genetically engineered animal models.
复制标题
β-肾上腺素能受体信号传导：一种急性代偿性调整——不适用于心力衰竭的慢性应激？
DOI：
10.1161/01.res.86.5.502
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发表时间：
2000
影响因子：
20.1
通讯作者：
Homcy,CJ
中科院分区：
文献类型：
--
作者：
Vatner,SF;Vatner,DE;Homcy,CJ
Under normal physiological conditions, the heart must be able to increase its output 5-fold to supply the required blood flow to the coronary circulation and skeletal muscles during severe stress. This is normally met by 5-fold increases in myocardial contractility, 3-fold increases in heart rate, and additional increases in stroke volume. 1 This increased load requires a commensurate increase in myocardial blood flow, because oxygen extraction across the heart is nearly complete, even under normal conditions. Accordingly, the design of the cardiovascular system evolved to conserve myocardial metabolic demand, and consequently coronary blood flow, at rest, but with considerable reserve that can be called on rapidly in times of stress. There is a host of compensatory adjustments, including changes in metabolic substrates and kinetics, as well as oxygen-carrying capacity, that may be recruited in response to stress. However, none is more important than the autonomic nervous system in general, and the sympathetic arm in particular, in terms of providing large, rapid changes in cardiac function. When this compensatory mechanism is unavailable, eg, after treatment with propranolol, the 3-fold increases in heart rate and 5-fold increases in myocardial contractility in response to exercise cannot be achieved. 1In this connection, it is recognized that heart failure is a state characterized by enhanced sympathetic tone, but when the failing myocardium is challenged by ß-adrenergic stimulation in vivo or in vitro, the most frequent result is ß-adrenergic downregulation or desensitization. 2–5 An im-
