Sympathetic modulation of blood pressure variability
作者:
Claude Julien,
Simon Malpas,
Harald Stauss,
期刊:
Journal of Hypertension
(OVID Available online 2001)
卷期:
Volume 19,
issue 10
页码: 1707-1712
ISSN:0263-6352
年代: 2001
出版商: OVID
关键词: blood pressure variability;frequency response;sympathetic nervous system
数据来源: OVID
摘要:
Although sympathetic nervous activity (SNA) displays oscillations synchronous with the heart beat and respiration, and between 0.1–0.4 Hz, it is apparent that each of these frequencies does not have the same effect on the vasculature. Frequencies above1Hz do not produce oscillations in the vasculature but instead contribute to the mean level of vasoconstriction. Slower oscillations in SNA result in a cycle of vasoconstriction and vasodilation within the vasculature, the amplitude of which, generally decreases with increasing frequency. Some studies indicate that, within the same species, differences exist in the frequency responses between vascular beds, such as the skin and gut. This differential responsiveness is also found between the medullary and cortical vasculature regions of the rabbit kidney. Low-pass filter properties have been described in the iliac circulation of rats, and evidence has been provided that noradrenaline reuptake mechanisms are not the frequency limiting step of the vasculature response. Recent studies on isolated rat vascular smooth muscle cells suggest that sympathetic modulation of vascular tone is limited by the α-adrenoceptor signal transduction into the cells and not by an intrinsic inability of the cells to contract and relax at higher rates.
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