Ascorbic acid improves postischemic vasodilatation impaired by infusion of soybean oil into canine iliac artery.
This study was conducted to (a) assess postischemic vasodilatation by changes in the vascular cross-sectional area using simultaneous intravascular two-dimensional and Doppler ultrasound before and after the infusion of Intralipid (Pharmacia & Upjohn, Peapack, NJ, U.S.A.); (b) evaluate how antioxidant ascorbic acid modifies the effects of Intralipid on postischemic vasodilatation: and (c) clarify the changes in plasma nitrite and nitrate (NOx-) levels after the infusion of Intralipid with and without ascorbic acid. Twenty-eight mongrel dogs were used to measure for vascular cross-sectional area and average instantaneous peak velocity in the iliac arteries after the 5-min occlusion of the arteries. Postischemic vasodilatation was impaired after the infusion of Intralipid (20%, 2 ml/kg) and this impaired response was reversed by the co-administration of ascorbic acid (30 mg/kg). NG-monomethyl-L-arginine completely abolished postischemic vasodilatation. Plasma NOx levels were significantly reduced after the infusion of Intralipid compared with baseline (11.6+/-0.4 vs. 12.9+/-0.3 microM, p = 0.025) and after infusion of Intralipid with ascorbic acid compared with baseline (11.8+/-0.5 vs. 13.1+/-0.4 microM, p = 0.047). We concluded that ascorbic acid reverses the endothelial dysfunction induced by Intralipid without increasing plasma NOx- levels and that deactivation of nitric oxide by oxidative stress is a primary contributor to Intralipid-induced impaired vasodilation.
Osanai
H
H
Department of Internal Medicine II, Nagoya University School of Medicine, Japan.
Okumura
K
K
Hayakawa
M
M
Harada
M
M
Numaguchi
Y
Y
Mokuno
S
S
Murase
K
K
Matsui
H
H
Toki
Y
Y
Ito
T
T
Hayakawa
T
T
D000818:Animals; D001205:Ascorbic Acid / Q000494:pharmacology*; D002784:Cholesterol / Q000097:blood; D003326:Coronary Circulation / Q000187:drug effects; D004285:Dogs; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005217:Fat Emulsions, Intravenous / Q000494:pharmacology; D005260:Female; D007083:Iliac Artery / Q000033:anatomy & histology / Q000502:physiology*; D007262:Infusions, Intravenous; D007511:Ischemia / Q000503:physiopathology*; D008297:Male; D009566:Nitrates / Q000097:blood; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D052250:Nitric Oxide Synthase Type III; D009573:Nitrites / Q000097:blood; D013024:Soybean Oil / Q000008:administration & dosage / Q000494:pharmacology*; D014280:Triglycerides / Q000097:blood; D014664:Vasodilation / Q000187:drug effects*; D019323:omega-N-Methylarginine / Q000494:pharmacology
D004791:Enzyme Inhibitors; D005217:Fat Emulsions, Intravenous; D009566:Nitrates; D009573:Nitrites; D014280:Triglycerides; D019323:omega-N-Methylarginine; D013024:Soybean Oil; D002784:Cholesterol; D019001:Nitric Oxide Synthase; D052250:Nitric Oxide Synthase Type III; D001205:Ascorbic Acid