Time course of intermittent hypoxia-induced impairments in resistance artery structure and function.
We previously demonstrated that chronic exposure to intermittent hypoxia (CIH) impairs endothelium-dependent vasodilation in rats. To determine the time course of this response, rats were exposed to CIH for 3, 14, 28, or 56 days. Then, we measured acetylcholine- and nitroprusside-induced vasodilation in isolated gracilis arteries. Also, we measured endothelial and inducible nitric oxide synthase, nitrotyrosine, and collagen in the arterial wall and urinary isoprostanes. Endothelium-dependent vasodilation was impaired after 2 weeks of CIH. Three days of CIH was not sufficient to produce this impairment and longer exposures (i.e. 4 and 8 weeks) did not exacerbate it. Impaired vasodilation was accompanied by increased collagen deposition. CIH elevated urinary isoprostane excretion, whereas there was no consistent effect on either isoform of nitric oxide synthase or nitrotyrosine. Exposure to CIH produces functional and structural deficits in skeletal muscle resistance arteries. These impairments develop within 2 weeks after initiation of exposure and they are accompanied by systemic evidence of oxidant stress.
Philippi
Nathan R
NR
John Rankin Laboratory of Pulmonary Medicine, Department of Orthopedics and Rehabilitation, University of Wisconsin, Madison, WI, USA.
Bird
Cynthia E
CE
Marcus
Noah J
NJ
Olson
E Burt
EB
Chesler
Naomi C
NC
Morgan
Barbara J
BJ
D000109:Acetylcholine / Q000494:pharmacology; D000704:Analysis of Variance; D000818:Animals; D001158:Arteries / Q000187:drug effects / Q000473:pathology* / Q000503:physiopathology*; D002908:Chronic Disease; D003094:Collagen / Q000378:metabolism; D004730:Endothelium, Vascular / Q000473:pathology / Q000503:physiopathology*; D000860:Hypoxia / Q000139:chemically induced / Q000503:physiopathology*; D007150:Immunohistochemistry; D028421:Isoprostanes / Q000652:urine; D008297:Male; D018482:Muscle, Skeletal / Q000098:blood supply*; D020030:Nitric Oxide Donors / Q000494:pharmacology; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism; D009599:Nitroprusside / Q000494:pharmacology; D010100:Oxygen / Q000097:blood; D010313:Partial Pressure; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors; D014443:Tyrosine / Q000031:analogs & derivatives / Q000378:metabolism; D014655:Vascular Resistance / Q000187:drug effects*; D014664:Vasodilation / Q000187:drug effects*; D014665:Vasodilator Agents / Q000494:pharmacology
D028421:Isoprostanes; D020030:Nitric Oxide Donors; D014665:Vasodilator Agents; D009599:Nitroprusside; C002744:3-nitrotyrosine; D014443:Tyrosine; D003094:Collagen; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; D000109:Acetylcholine; D010100:Oxygen