| Discharge properties of cardiac and renal sympathetic nerves and their impaired responses to changes in blood volume in heart failure. | |
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MedLine Citation:
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PMID: 19535677 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Sympathetic nerve activity (SNA) consists of discharges that vary in amplitude and frequency, reflecting the level of recruitment of nerve fibers and the rhythmic generation and entrainment of activity by the central nervous system. It is unknown whether selective changes in these amplitude and frequency components account for organ-specific changes in SNA in response to alterations in blood volume or for the impaired SNA responses to volume changes in heart failure (HF). To address these questions, we measured cardiac SNA (CSNA) and renal SNA (RSNA) simultaneously in conscious, normal sheep and sheep in HF induced by rapid ventricular pacing. Volume expansion decreased CSNA (-62 +/- 10%, P < 0.05) and RSNA (-59 +/- 10%, P < 0.05) equally (n = 6). CSNA decreased as a result of a reduction in burst frequency, whereas RSNA fell because of falls in burst frequency and amplitude. Hemorrhage increased CSNA (+74 +/- 9%, P < 0.05) more than RSNA (+21 +/- 5%, P < 0.09), in both cases because of increased burst frequency, whereas burst amplitude decreased. In HF, burst frequency of CSNA (from 26 +/- 3 to 75 +/- 3 bursts/min) increased more than that of RSNA (from 63 +/- 4 to 79 +/- 4 bursts/min). In HF, volume expansion caused no change in CSNA and an attenuated decrease in RSNA, due entirely to decreased burst amplitude. Hemorrhage did not significantly increase SNA in either nerve in HF. These findings support the concept that the number of sympathetic fibers recruited and their firing frequency are controlled independently. Furthermore, afferent stimuli, such as changes in blood volume, cause organ-specific responses in each of these components, which are also selectively altered in HF. |
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Authors:
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R Ramchandra; S G Hood; R Frithiof; C N May |
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Publication Detail:
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Type: Comparative Study; Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't Date: 2009-06-17 |
Journal Detail:
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Title: American journal of physiology. Regulatory, integrative and comparative physiology Volume: 297 ISSN: 1522-1490 ISO Abbreviation: Am. J. Physiol. Regul. Integr. Comp. Physiol. Publication Date: 2009 Sep |
Date Detail:
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Created Date: 2009-08-25 Completed Date: 2009-09-10 Revised Date: 2010-09-02 |
Medline Journal Info:
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Nlm Unique ID: 100901230 Medline TA: Am J Physiol Regul Integr Comp Physiol Country: United States |
Other Details:
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Languages: eng Pagination: R665-74 Citation Subset: IM |
Affiliation:
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Howard Florey Institute, Univ. of Melbourne, Parkville, Victoria 3010, Australia. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Action Potentials Afferent Pathways / physiopathology Animals Blood Pressure Blood Volume* Disease Models, Animal Female Heart / innervation* Heart Failure / physiopathology* Heart Rate Hemorrhage / physiopathology* Kidney / innervation* Sheep Sympathetic Nervous System / physiopathology* Time Factors |
| Grant Support | |
ID/Acronym/Agency:
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5-R01-HL-074932/HL/NHLBI NIH HHS |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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