Effect of exercise training on aortic tone in chronic renal insufficiency.
BACKGROUND
Chronic renal insufficiency (CRI) is associated with a high incidence of hypertension (HTN), endothelial dysfunction, atherosclerosis and cardiovascular disease. Sedentary life style increases, whereas regular exercise reduces the risk of cardiovascular disease. This study was designed to test the effect of regular exercise on vasodilatory and vasoconstrictive responses of the thoracic aorta in rats with renal mass reduction.


METHODS
One week after 5/6 nephrectomy (CRI) or sham operation (control), rats were housed in either regular cages or cages equipped with running wheels for 4 weeks. Thereafter, thoracic aorta was harvested and contractile response to potassium and phenylephrine (PhE), and relaxation response to acetylcholine (ACh) and sodium nitroprusside (SNP) were determined.


RESULTS
Compared with the control animals, sedentary CRI animals exhibited significant azotemia, proteinuria, HTN, oxidative stress, and increased sensitivity to potassium and PhE, and reduced sensitivity to ACh and SNP. Exercise training for 4 weeks reduced oxidative stress, reversed CRI-induced heightened sensitivity of the aorta to PhE and potassium, and restored its sensitivity to ACh (but not SNP) without affecting arterial pressure or renal function.


CONCLUSIONS
CRI results in heightened sensitivity to potassium- and alpha-1 adrenergic-mediated contractility and depressed sensitivity to endothelium-dependent relaxation in the aorta. Regular exercise improves these abnormalities without affecting arterial pressure or renal function. These observations suggest that exercise training can improve vascular function in animals, and perhaps humans, with chronic kidney disease.
Shelkovnikov
Stan
S
Department of Pharmacology, University of California Irvine, Irvine, California, USA.
Summers
Scott M
SM
Elahimehr
Reza
R
Adams
Gregory
G
Purdy
Ralph E
RE
Vaziri
Nosratola D
ND
D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects / Q000503:physiopathology*; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D008297:Male; D009392:Nephrectomy; D009599:Nitroprusside / Q000494:pharmacology; D010656:Phenylephrine / Q000494:pharmacology; D005082:Physical Exertion; D011189:Potassium Chloride / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D051436:Renal Insufficiency, Chronic / Q000378:metabolism / Q000503:physiopathology*; D014661:Vasoconstriction / Q000187:drug effects; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D014664:Vasodilation / Q000187:drug effects; D014665:Vasodilator Agents / Q000494:pharmacology
D014662:Vasoconstrictor Agents; D014665:Vasodilator Agents; D009599:Nitroprusside; D010656:Phenylephrine; D011189:Potassium Chloride; D000109:Acetylcholine