Document Detail

Role of nitric oxide in exercise-induced vasodilation of the forearm.
MedLine Citation:
PMID:  7994834     Owner:  NLM     Status:  MEDLINE    
BACKGROUND: We wished to determine the role of NO in exercise-induced metabolic forearm vasodilation. METHODS AND RESULTS: Young healthy volunteers (n = 11) underwent static handgrip exercise (4 to 5 kg, 3 minutes). Forearm blood flow (FBF) measured by strain plethysmography increased from 4.1 +/- 0.7 mL.min-1.100 mL-1 at rest to 9.8 +/- 1.2 mL.min-1.100 mL-1 immediately after exercise and gradually decreased thereafter. Exercise was repeated after intrabrachial artery infusion of NG-monomethyl-L-arginine (L-NMMA) at 4.0 mumol/min for 5 minutes. L-NMMA did not alter blood pressure and heart rate. L-NMMA decreased FBF at rest to 2.9 +/- 0.4 mL.min-1.100 mL-1 (P < .01), peak FBF immediately after exercise to 7.2 +/- 0.7 mL.min-1.100 mL-1 (P < .01), and FBF during the mid to late phase of metabolic vasodilation (P < .01). Calculated oxygen consumption during peak exercise was comparable before and after L-NMMA. Intra-arterially infused L-arginine (10 mg/min, 5 minutes) reversed the inhibitory effect of L-NMMA. To determine the effect of the decrease in resting FBF on exercise-induced hyperemia, we normalized FBF after exercise by resting FBF. The percent increases in FBF after exercise from resting FBF were similar before and after L-NMMA. Furthermore, we examined the effect of intra-arterially infused angiotensin II on FBF at rest and after exercise (n = 7). Angiotensin II decreased FBF at rest from 3.1 +/- 0.3 to 1.8 +/- 0.3 mL.min-1.100 mL-1 (P < .01), peak FBF after exercise from 8.1 +/- 0.5 to 5.6 +/- 0.5 mL.min-1.100 mL-1 (P < .01), and FBF during the mid to late phase of metabolic vasodilation. The effects of L-NMMA and angiotensin II on FBF at rest and exercise were similar. CONCLUSIONS: Our results suggest that L-NMMA decreased FBF after exercise largely by decreasing resting FBF. These results suggest that NO may not play a significant role in exercise-induced metabolic arteriolar vasodilation in the forearm of healthy humans.
T Endo; T Imaizumi; T Tagawa; M Shiramoto; S Ando; A Takeshita
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Circulation     Volume:  90     ISSN:  0009-7322     ISO Abbreviation:  Circulation     Publication Date:  1994 Dec 
Date Detail:
Created Date:  1995-01-17     Completed Date:  1995-01-17     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  0147763     Medline TA:  Circulation     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  2886-90     Citation Subset:  AIM; IM    
Research Institute of Angiocardiology, Faculty of Medicine, Kyushu University, Fukuoka, Japan.
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MeSH Terms
Angiotensin II / pharmacology
Arginine / analogs & derivatives,  pharmacology
Forearm / blood supply*
Injections, Intra-Arterial
Nitric Oxide / antagonists & inhibitors,  physiology*
Physical Exertion*
Regional Blood Flow / drug effects
Vasodilation / physiology*
Reg. No./Substance:
10102-43-9/Nitric Oxide; 11128-99-7/Angiotensin II; 17035-90-4/omega-N-Methylarginine; 74-79-3/Arginine

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

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