Document Detail


Nitric oxide and attenuated reflex cutaneous vasodilation in aged skin.
MedLine Citation:
PMID:  12505876     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Thermoregulatory cutaneous vasodilation is diminished in the elderly. The goal of this study was to test the hypothesis that a reduction in nitric oxide (NO)-dependent mechanisms contributes to the attenuated reflex cutaneous vasodilation in older subjects. Seven young (23 +/- 2 yr) and seven older (71 +/- 6 yr) men were instrumented with two microdialysis fibers in the forearm skin. One site served as control (Ringer infusion), and the second site was perfused with 10 mM N(G)-nitro-l-arginine methyl ester to inhibit NO synthase (NOS) throughout the protocol. Water-perfused suits were used to raise core temperature 1.0 degrees C. Red blood cell (RBC) flux was measured with laser-Doppler flowmetry over each microdialysis fiber. Cutaneous vascular conductance (CVC) was calculated as RBC flux per mean arterial pressure, with values expressed as a percentage of maximal vasodilation (infusion of 28 mM sodium nitroprusside). NOS inhibition reduced CVC from 75 +/- 6% maximal CVC (CVC(max)) to 53 +/- 3% CVC(max) in the young subjects and from 64 +/- 5% CVC(max) to 29 +/- 2% CVC(max) in the older subjects with a 1.0 degrees C rise in core temperature. Thus the relative NO-dependent portion of cutaneous active vasodilation (AVD) accounted for approximately 23% of vasodilation in the young subjects and 60% of the vasodilation in the older subjects at this level of hyperthermia (P < 0.001). In summary, NO-mediated pathways contributed more to the total vasodilatory response of the older subjects at high core temperatures. This suggests that attenuated cutaneous vasodilation with age may be due to a reduction in, or decreased vascular responsiveness to, the unknown neurotransmitter(s) mediating AVD.
Authors:
Lacy A Holowatz; Belinda L Houghton; Brett J Wong; Brad W Wilkins; Aaron W Harding; W Larry Kenney; Christopher T Minson
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Publication Detail:
Type:  Clinical Trial; Comparative Study; Journal Article; Research Support, U.S. Gov't, P.H.S.     Date:  2002-12-27
Journal Detail:
Title:  American journal of physiology. Heart and circulatory physiology     Volume:  284     ISSN:  0363-6135     ISO Abbreviation:  Am. J. Physiol. Heart Circ. Physiol.     Publication Date:  2003 May 
Date Detail:
Created Date:  2003-04-07     Completed Date:  2003-05-15     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  100901228     Medline TA:  Am J Physiol Heart Circ Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  H1662-7     Citation Subset:  IM    
Affiliation:
Department of Exercise and Movement Science, University of Oregon, Eugene, OR 97403-1240, USA.
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MeSH Terms
Descriptor/Qualifier:
Adult
Aged
Aging / metabolism*
Body Temperature Regulation / physiology
Enzyme Inhibitors / administration & dosage
Fever / metabolism
Humans
Male
Microdialysis
NG-Nitroarginine Methyl Ester / administration & dosage
Nitric Oxide / metabolism*
Nitric Oxide Synthase / antagonists & inhibitors
Reflex / physiology*
Regional Blood Flow / physiology
Skin / blood supply*,  innervation
Skin Temperature / physiology
Vasodilation / physiology*
Grant Support
ID/Acronym/Agency:
R01 AG 07004-11/AG/NIA NIH HHS
Chemical
Reg. No./Substance:
0/Enzyme Inhibitors; 10102-43-9/Nitric Oxide; 50903-99-6/NG-Nitroarginine Methyl Ester; EC 1.14.13.39/Nitric Oxide Synthase

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


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