Nitric oxide (NO) is an important physiological regulator of vascular function. Recent data indicate that NO also has a significant role in the modulation of tissue oxygen consumption. The roles of NO in skeletal muscle hyperemia and oxygen consumption in humans are unclear. There are no definitive data regarding whether NO production increases in skeletal muscle during exercise. Whether NO contributes to the regulation of skeletal muscle oxygen uptake at rest and during exercise in humans is also unclear. The proposed experiments will test 1) whether NO production in skeletal muscle increases during dynamic exercise; 2) whether NO produced during exercise in skeletal muscle contributes to the hyperemia associated with exercise; and 3) whether endogenous NO modulates skeletal muscle oxygen consumption at rest and during exercise. We will measure the conversion of arginine to citrulline, using stable isotope techniques, as a direct index of endothelial NO production; we will also use blockade of NO synthesis via infusion of L-NMMA. Exercising muscle oxygen consumption (VO2) will be measured directly and whole body VO2 will be measured at the mouth. The strength of the proposed experimental design is that we will study basic mechanisms of circulatory control during exercise in humans. The results of these experiments will provide important new information about the mechanistic role of NO in the regulation of skeletal muscle blood flow and oxygen consumption in humans.

Agency
National Institute of Health (NIH)
Institute
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Type
Postdoctoral Individual National Research Service Award (F32)
Project #
1F32AR008610-01
Application #
6139926
Study Section
Special Emphasis Panel (ZRG1-ALTX-1 (03))
Program Officer
Lymn, Richard W
Project Start
2000-09-01
Project End
Budget Start
2000-09-01
Budget End
2001-08-31
Support Year
1
Fiscal Year
2000
Total Cost
$32,416
Indirect Cost
Name
Mayo Clinic, Rochester
Department
Type
DUNS #
City
Rochester
State
MN
Country
United States
Zip Code
55905
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Charkoudian, Nisha (2003) Skin blood flow in adult human thermoregulation: how it works, when it does not, and why. Mayo Clin Proc 78:603-12
Charkoudian, N; Vella, A; Reed, A S et al. (2002) Cutaneous vascular function during acute hyperglycemia in healthy young adults. J Appl Physiol 93:1243-50
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Charkoudian, Nisha; Eisenach, John H; Atkinson, John L D et al. (2002) Effects of chronic sympathectomy on locally mediated cutaneous vasodilation in humans. J Appl Physiol 92:685-90
Eisenach, John H; Clark, Erin S; Charkoudian, Nisha et al. (2002) Effects of chronic sympathectomy on vascular function in the human forearm. J Appl Physiol 92:2019-25