Document Detail


Baroreflex control of muscle sympathetic nerve activity: a nonpharmacological measure of baroreflex sensitivity.
MedLine Citation:
PMID:  20008270     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The sensitivity of baroreflex control of sympathetic nerve activity (SNA) represents the responsiveness of SNA to changes in blood pressure. In a slightly different analysis, the baroreflex threshold measures the probability of whether a sympathetic burst will occur at a given diastolic blood pressure. We hypothesized that baroreflex threshold analysis could be used to estimate the sensitivity of the sympathetic baroreflex measured by the pharmacological modified Oxford test. We compared four measures of sympathetic baroreflex sensitivity in 25 young healthy participants: the "gold standard" modified Oxford analysis (nitroprusside and phenylephrine), nonbinned spontaneous baroreflex analysis, binned spontaneous baroreflex analysis, and threshold analysis. The latter three were performed during a quiet baseline period before pharmacological intervention. The modified Oxford baroreflex sensitivity was significantly related to the threshold slope (r = 0.71, P < 0.05) but not to the binned (1 mmHg bins) and the nonbinned spontaneous baroreflex sensitivity (r = 0.22 and 0.36, respectively, P > 0.05), which included burst area. The threshold analysis was also performed during the modified Oxford manipulation. Interestingly, we found that the threshold analysis results were not altered by the vasoactive drugs infused for the modified Oxford. We conclude that the noninvasive threshold analysis technique can be used as an indicator of muscle SNA baroreflex sensitivity as assessed by the modified Oxford technique. Furthermore, the modified Oxford method does not appear to alter the properties of the baroreflex.
Authors:
Emma C Hart; Michael J Joyner; B Gunnar Wallin; Tomas Karlsson; Timothy B Curry; Nisha Charkoudian
Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't     Date:  2009-12-11
Journal Detail:
Title:  American journal of physiology. Heart and circulatory physiology     Volume:  298     ISSN:  1522-1539     ISO Abbreviation:  Am. J. Physiol. Heart Circ. Physiol.     Publication Date:  2010 Mar 
Date Detail:
Created Date:  2010-02-25     Completed Date:  2010-04-02     Revised Date:  2013-05-31    
Medline Journal Info:
Nlm Unique ID:  100901228     Medline TA:  Am J Physiol Heart Circ Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  H816-22     Citation Subset:  IM    
Affiliation:
Dept. of Anesthesiology, Mayo Clinic, Rochester, MN 59906, USA. hart.emma@mayo.edu
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MeSH Terms
Descriptor/Qualifier:
Adult
Baroreflex / physiology*
Blood Pressure / drug effects,  physiology*
Female
Humans
Male
Muscle, Skeletal / innervation*,  physiology
Nitroprusside / pharmacology
Phenylephrine / pharmacology
Sensitivity and Specificity
Sympathetic Nervous System / physiology*
Vasoconstrictor Agents / pharmacology
Vasodilator Agents / pharmacology
Grant Support
ID/Acronym/Agency:
1-UL1-RR-024150/RR/NCRR NIH HHS; DK-082424/DK/NIDDK NIH HHS; HL-83947/HL/NHLBI NIH HHS; R01 HL083947-05/HL/NHLBI NIH HHS
Chemical
Reg. No./Substance:
0/Vasoconstrictor Agents; 0/Vasodilator Agents; 15078-28-1/Nitroprusside; 59-42-7/Phenylephrine
Comments/Corrections

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