Document Detail

Cardiovascular autonomic function in conscious rats: a novel approach to facilitate stationary conditions.
MedLine Citation:
PMID:  12431308     Owner:  NLM     Status:  MEDLINE    
BACKGROUND: An experimental setting and software were developed to evaluate cardiovascular autonomic function in conscious rats. A restrained approach was used, which, upon proper habituation, induced little or no stress in the rats and limited motion artifacts. METHODS: The ECG and arterial blood pressure were recorded. Time- and frequency-domain indices of heart rate variability (HRV) and blood pressure variability (BPV) were calculated. The spontaneous baroreflex sensitivity (spBRS) was estimated using the method of statistical dependence. RESULTS: The power spectra clearly concentrated in a frequency band with center frequency around 0.4 Hz, the low frequency (LF) component, and one at the respiratory frequency at 1.5 Hz, the high frequency (HF) component. In baseline conditions, a direct association existed between mean R-R and especially HRV parameters denoting vagal modulation such as rMSSD, pNN5, and HF power. Beta-adrenergic blockade by propranolol diminished basal heart rate. Vagal indices increased while there was an exclusive decrease in the low frequency band of HRV. Alpha-adrenergic blockade with phentolamine produced a depressor response with tachycardia, and a clear decrease in the LF component of BPV. Both the LF and HF component in the HRV spectrum were virtually absent. Cholinergic blockade with atropine did not significantly alter BP but induced a clear tachycardia with decreased vagal indices. The HF component of HRV was completely abolished and the LF band was reduced. CONCLUSIONS: Both alpha- and beta-adrenergic blockade left spBRS virtually unaltered, while cholinergic blockade profoundly diminished spBRS. Spectral fluctuations of beta-sympathetic tone were restricted to the LF range of HRV, while the HF respiratory component represented vagal modulation. The alpha-sympathetic system played a dominant role in the LF oscillations of BPV. A role of the vagus in the HF oscillations of BPV in the rat is questioned. The baroreflex depended mainly on changes in vagal activity.
Dirk Ramaekers; Frank Beckers; Hilde Demeulemeester; André E Aubert
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Annals of noninvasive electrocardiology : the official journal of the International Society for Holter and Noninvasive Electrocardiology, Inc     Volume:  7     ISSN:  1082-720X     ISO Abbreviation:  Ann Noninvasive Electrocardiol     Publication Date:  2002 Oct 
Date Detail:
Created Date:  2002-11-14     Completed Date:  2003-04-14     Revised Date:  2008-03-10    
Medline Journal Info:
Nlm Unique ID:  9607443     Medline TA:  Ann Noninvasive Electrocardiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  307-18     Citation Subset:  IM    
Dept. of Cardiology, University Hospital Gasthuisberg O-N, Herestraat 49, B-3000 Leuven, Belgium.
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MeSH Terms
Adrenergic alpha-Antagonists / pharmacology*
Adrenergic beta-Antagonists / pharmacology*
Baroreflex / drug effects*
Blood Pressure / drug effects*
Heart Rate / drug effects*
Phentolamine / pharmacology
Propranolol / pharmacology
Rats, Wistar
Reg. No./Substance:
0/Adrenergic alpha-Antagonists; 0/Adrenergic beta-Antagonists; 50-60-2/Phentolamine; 525-66-6/Propranolol

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

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