Document Detail

Effects of autonomic blockade on non-linear cardiovascular variability indices in rats.
MedLine Citation:
PMID:  16700875     Owner:  NLM     Status:  MEDLINE    
1. The present study assesses the effects of autonomic blockade (alpha- and beta-adrenoceptor and cholinergic) on cardiovascular function studied by heart rate variability (HRV), blood pressure variability (BPV) and baroreflex sensitivity in rats using non-linear dynamics. Little is known about the influence of pharmacological autonomic nervous system interventions on non-linear cardiovascular regulatory indices. 2. In 13 conscious rats, heart rate and aortic blood pressure were measured continuously before, during and after autonomic blockade with atropine, phentolamine and propranolol. Non-linear scaling properties were studied using 1/f slope, fractal dimension and long- and short-term correlation. Non-linear complexity was described with correlation dimension, Lyapunov exponent and approximate entropy. Non-linear indices were compared with linear time and frequency domain indices. 3. Beta-adrenoceptor blockade did not alter the non-linear characteristics of HRV and BPV, although low-frequency power of HRV was depressed. Alpha-adrenoceptor blockade decreased the scaling behaviour of HRV, whereas cholinergic blockade decreased the complexity of the non-linear system of HRV. For BPV, the scaling behaviour was increased during alpha-adrenoceptor blockade and the complexity was increased during cholinergic blockade. The linear indices of HRV and BPV were decreased. 4. The present results indicate that the beta-adrenoceptor system has little involvement in the generation of non-linear HRV and BPV in rats. 5. Alpha-adrenoceptor blockade mostly influenced the scaling properties of the time series, whereas cholinergic blockade induced changes in the complexity measures. 6. The absence of the baroreflex mechanism can trigger a compensatory feed-forward system increasing the complexity of BPV.
Frank Beckers; Bart Verheyden; Dirk Ramaekers; Bernard Swynghedauw; André E Aubert
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Clinical and experimental pharmacology & physiology     Volume:  33     ISSN:  0305-1870     ISO Abbreviation:  Clin. Exp. Pharmacol. Physiol.     Publication Date:    2006 May-Jun
Date Detail:
Created Date:  2006-05-16     Completed Date:  2007-08-08     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0425076     Medline TA:  Clin Exp Pharmacol Physiol     Country:  Australia    
Other Details:
Languages:  eng     Pagination:  431-9     Citation Subset:  IM    
Laboratory of Experimental Cardiology, School of Medicine, Gasthuisberg University Hospital, KU Leuven, Leuven, Belgium.
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MeSH Terms
Adrenergic alpha-Antagonists / pharmacology*
Adrenergic beta-Antagonists / pharmacology
Atropine / pharmacology
Autonomic Nervous System / drug effects*
Blood Pressure
Heart Rate
Models, Cardiovascular
Muscarinic Antagonists / pharmacology*
Nonlinear Dynamics
Phentolamine / pharmacology
Propranolol / pharmacology
Rats, Wistar
Reg. No./Substance:
0/Adrenergic alpha-Antagonists; 0/Adrenergic beta-Antagonists; 0/Muscarinic Antagonists; 50-60-2/Phentolamine; 51-55-8/Atropine; 525-66-6/Propranolol

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