| The sympathetic nervous system and baroreflexes in hypertension and hypotension. | |
| | |
MedLine Citation:
|
PMID: 10981075 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
|
Blood pressure and blood volume are closely regulated by the interrelated actions of the sympathetic nervous system (SNS) and the renin-angiotensin-aldosterone system (RAAS). Reflex vasoconstriction caused by parallel SNS and RAAS activation is modulated by two interactive negative feedback systems called baroreflex. The aortic-carotid baroreflex systems respond to momentary changes in systolic blood pressure, adjusting the degree of SNS-dependent peripheral vasoconstriction and cardiac output to allow maintenance of a relatively constant perfusion pressure. Cardiopulmonary baroreflexes respond to momentary changes in cardiac filling, adjusting the degree of peripheral venoconstriction and venous return to maintain cardiac preload and stroke volume. Under normal conditions, each baroreflex system exhibits a degree of tonic negative feedback so that it can alter SNS output immediately, providing counterregulatory increases or decreases in pressure or volume to maintain homeostasis. The SNS is inappropriately active in obesity and hypertension and plays a causal or permissive role in all forms of chronic hypertension. If the negative feedback control exerted by the baroreflexes over the SNS and renin-angiotensin-aldosterone system (RAAS) were perfect, chronic hypertension would not occur. Activity of the baroreflexes, however, is chronically altered by maladaptive changes such as cardiac and vascular fibrosis and hypertrophy. Long-term increases in SNS and RAAS activity also exert ongoing deleterious effects on the heart and vasculature by directly facilitating further cardiac hypertrophy and arterial stiffening. These effects appear to contribute to a vicious cycle of chronic hypertension and target organ damage. Other syndromes of abnormal blood pressure (BP) control, including orthostatic hypotension and baroreflex failure are examples of abnormal baroreflex activity and SNS control. |
| | |
Authors:
|
J L Izzo; A A Taylor |
Related Documents
:
|
2155075 - Failure to visualize bilateral adrenal glands in a patient with primary aldosteronism. 7894215 - Evidence for cardiovascular remodeling in a patient with bartter's syndrome. 7408785 - Blood pressure response to an angiotensin ii antagonist in thyrotoxic patients with and... 16333235 - Nesiritide: past, present, and future. 7669305 - Cardiac output measurement: lack of agreement between thermodilution and thoracic elect... 15530195 - Tezosentan, a combined parenteral endothelin receptor antagonist, produces pulmonary va... |
Publication Detail:
|
Type: Journal Article; Review |
Journal Detail:
|
Title: Current hypertension reports Volume: 1 ISSN: 1522-6417 ISO Abbreviation: Curr. Hypertens. Rep. Publication Date: 1999 Jun |
Date Detail:
|
Created Date: 2000-10-23 Completed Date: 2000-10-23 Revised Date: 2006-07-12 |
Medline Journal Info:
|
Nlm Unique ID: 100888982 Medline TA: Curr Hypertens Rep Country: UNITED STATES |
Other Details:
|
Languages: eng Pagination: 254-63 Citation Subset: IM |
Affiliation:
|
State University of New York at Buffalo, Buffalo, New York 14214 USA. |
Export Citation:
|
APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
|
Animals Baroreflex / physiology* Carotid Body / physiology Cerebral Cortex / physiology Heart / physiology Homeostasis Humans Hypertension / physiopathology* Hypertrophy, Left Ventricular / physiopathology Hypotension / physiopathology* Lung / physiology Sympathetic Nervous System / physiopathology* |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
Previous Document: The role of the central nervous system in hypertension.
Next Document: Brainstem compression as a cause of neurogenic hypertension.