Document Detail


Potentiated sympathetic nervous and renin-angiotensin systems reduce nonlinear correlation between sympathetic activity and blood pressure in conscious spontaneously hypertensive rats.
MedLine Citation:
PMID:  12147546     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
BACKGROUND: Patients with a reduced nonlinear component of heart rate regulation have a poorer outcome.
METHODS AND RESULTS: We investigated whether a nonlinear correlation between renal sympathetic nerve activity (RSNA) and blood pressure or renal blood flow is reduced in conscious, spontaneously hypertensive rats (SHR) by comparing them with normotensive Wistar-Kyoto rats (WKY). We also determined the linearity and nonlinearity of the correlation in SHR who were given an angiotensin II receptor blocker, candesartan, orally for 2 weeks. The RSNA value was higher in SHR than in WKY, and coherence peaks of transfer function were found at 0.05 and 0.80 Hz (ie, below respiratory- and cardiac-related fluctuations). The coherence (linearity) of the transfer function was significantly higher and gain was smaller in SHR than in WKY. Because mutual information values (linear and nonlinear correlation) were similar in both strains, we found the nonlinear correlation to be lower in SHR than in WKY. Time delay values calculated by the mutual information method demonstrated that RSNA preceded blood pressure and renal blood flow by 0.5 to 1.0 s. In SHR given candesartan, the RSNA value was lower, and the linearity was lower and nonlinearity higher than SHR given vehicle.
CONCLUSIONS: Linear correlation between RSNA and blood pressure or renal blood flow was higher in SHR than in WKY, whereas the nonlinear correlation was lower. Oral treatment with candesartan increased the nonlinearity and reduced the linearity in SHR. Increased RSNA and the renin-angiotensin system may be responsible for the lower nonlinearity and higher linearity in hypertension.
Authors:
Katsufumi Sakata; Hiroo Kumagai; Motohisa Osaka; Toshiko Onami; Tomokazu Matsuura; Masaki Imai; Takao Saruta
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Circulation     Volume:  106     ISSN:  1524-4539     ISO Abbreviation:  Circulation     Publication Date:  2002 Jul 
Date Detail:
Created Date:  2002-07-30     Completed Date:  2002-08-07     Revised Date:  2013-05-28    
Medline Journal Info:
Nlm Unique ID:  0147763     Medline TA:  Circulation     Country:  United States    
Other Details:
Languages:  eng     Pagination:  620-5     Citation Subset:  AIM; IM    
Affiliation:
Department of Internal Medicine, Keio University School of Medicine, Tokyo, Japan.
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MeSH Terms
Descriptor/Qualifier:
Administration, Oral
Angiotensin Receptor Antagonists
Animals
Arginine / administration & dosage
Benzimidazoles / administration & dosage
Blood Flow Velocity / drug effects
Blood Pressure* / drug effects
Electrocardiography / drug effects
Heart Rate / drug effects
Hypertension / drug therapy*,  physiopathology*
Infusions, Intravenous
Kidney / blood supply,  drug effects,  innervation
Male
Rats
Rats, Inbred SHR
Rats, Inbred WKY
Renin-Angiotensin System* / drug effects
Sympathetic Nervous System / drug effects,  physiopathology*
Tetrazoles / administration & dosage
Wakefulness
Chemical
Reg. No./Substance:
0/Angiotensin Receptor Antagonists; 0/Benzimidazoles; 0/Tetrazoles; 74-79-3/Arginine; S8Q36MD2XX/candesartan

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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