Document Detail

Exaggerated sympathetic and pressor responses to handgrip exercise in older hypertensive humans: role of the muscle metaboreflex.
MedLine Citation:
PMID:  20802135     Owner:  NLM     Status:  MEDLINE    
Recent animal studies have reported that exercise pressor reflex (EPR)-mediated increases in blood pressure are exaggerated in hypertensive (HTN) rodents. Whether these findings can be extended to human hypertension remains unclear. Mean arterial pressure (MAP), muscle sympathetic nerve activity (MSNA), and venous metabolites were measured in normotensive (NTN; n = 23; 60 ± 1 yr) and HTN (n = 15; 63 ± 1 yr) subjects at baseline, and during static handgrip at 30 and 40% maximal voluntary contraction (MVC) followed by a period of postexercise ischemia (PEI) to isolate the metabolic component of the EPR. Changes in MAP from baseline were augmented in HTN subjects during both 30 and 40% MVC handgrip (P < 0.05 for both), and these group differences were maintained during PEI (30% PEI trial: Δ15 ± 2 NTN vs. Δ19 ± 2 HTN mmHg; 40% PEI trial: Δ16 ± 1 NTN vs. Δ23 ± 2 HTN mmHg; P < 0.05 for both). Similarly, in HTN subjects, MSNA burst frequency was greater during 30 and 40% MVC handgrip (P < 0.05 for both), and these differences were maintained during PEI [30% PEI trial: 35 ± 2 (NTN) vs. 44 ± 2 (HTN) bursts/min; 40% PEI trial: 36 ± 2 (NTN) vs. 48 ± 2 (HTN) bursts/min; P < 0.05 for both]. No group differences in metabolites were observed. MAP and MSNA responses to a cold pressor test were not different between groups, suggesting no group differences in generalized sympathetic responsiveness. In summary, compared with NTN subjects, HTN adults exhibit exaggerated sympathetic and pressor responses to handgrip exercise that are maintained during PEI, indicating that activation of the metabolic component of the EPR is augmented in older HTN humans.
Erin P Delaney; Jody L Greaney; David G Edwards; William C Rose; Paul J Fadel; William B Farquhar
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't     Date:  2010-08-27
Journal Detail:
Title:  American journal of physiology. Heart and circulatory physiology     Volume:  299     ISSN:  1522-1539     ISO Abbreviation:  Am. J. Physiol. Heart Circ. Physiol.     Publication Date:  2010 Nov 
Date Detail:
Created Date:  2010-11-01     Completed Date:  2010-11-29     Revised Date:  2014-09-19    
Medline Journal Info:
Nlm Unique ID:  100901228     Medline TA:  Am J Physiol Heart Circ Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  H1318-27     Citation Subset:  IM    
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MeSH Terms
Aging / physiology*
Baroreflex / physiology
Blood Pressure / physiology
Cardiovascular Physiological Phenomena
Case-Control Studies
Exercise / physiology*
Hand Strength / physiology*
Hypertension / physiopathology*
Middle Aged
Muscle Contraction / physiology
Muscle, Skeletal / innervation*,  physiology*
Myocardial Ischemia / epidemiology,  physiopathology
Risk Factors
Sympathetic Nervous System / physiology*
Grant Support
Comment In:
Am J Physiol Heart Circ Physiol. 2010 Nov;299(5):H1302-3   [PMID:  20852038 ]

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