Oxidized low-density lipoproteins inhibit endothelium-dependent relaxations in isolated large and small rabbit coronary arteries. 1996

C Buckley, and S J Bund, and F McTaggart, and K R Bruckdorfer, and A Oldham, and M Jacobs
Department of Pharmacology, Royal Free Hospital School of Medicine, London, UK.

1. Previous studies suggest that oxidatively modified low-density lipoproteins (oxLDL) contribute to the impairment of endothelium-dependent vasodilation in the large arteries of hypercholesterolaemic animals, whereas this may not be the case with regard to the impairment of coronary resistance vessels. For this reason, the effect of lipoproteins on coronary resistance arteries has been examined in this study. 2. The influence of lipoproteins on endothelium-dependent relaxation induced by acetylcholine (ACh) or sodium nitroprusside in PGF2 alpha-preconstricted rings from the large (1st order branch) and small coronary arteries (3rd order branch) and the aorta of New Zealand White rabbits, was investigated. 3. The sensitivity to ACh was greater in the large compared with the small diameter coronary arteries. 4. Endothelium-dependent relaxations were unaffected by native LDL. Oxidized LDL (0.5 and 1 mg protein mL-1) caused a reversible inhibition of relaxations in both preconstricted small and large coronary arteries which was overcome at high ACh concentrations. Similar inhibitions were found in the aorta. 5. Endothelium-independent relaxations elicited by sodium nitroprusside in the large and small coronary arteries were unaffected by the oxidized lipoproteins, indicating that soluble guanylate cyclase activity was unaltered. 6. It is concluded that inhibition of endothelium-dependent relaxation in the small diameter coronary arteries in hypercholesterolaemia may arise from products of oxidative modification of LDL present in the artery itself or released upstream from proximal lesions.

UI MeSH Term Description Entries
D008077 Lipoproteins, LDL A class of lipoproteins of small size (18-25 nm) and light (1.019-1.063 g/ml) particles with a core composed mainly of CHOLESTEROL ESTERS and smaller amounts of TRIGLYCERIDES. The surface monolayer consists mostly of PHOSPHOLIPIDS, a single copy of APOLIPOPROTEIN B-100, and free cholesterol molecules. The main LDL function is to transport cholesterol and cholesterol esters to extrahepatic tissues. Low-Density Lipoprotein,Low-Density Lipoproteins,beta-Lipoprotein,beta-Lipoproteins,LDL(1),LDL(2),LDL-1,LDL-2,LDL1,LDL2,Low-Density Lipoprotein 1,Low-Density Lipoprotein 2,LDL Lipoproteins,Lipoprotein, Low-Density,Lipoproteins, Low-Density,Low Density Lipoprotein,Low Density Lipoprotein 1,Low Density Lipoprotein 2,Low Density Lipoproteins,beta Lipoprotein,beta Lipoproteins
D009119 Muscle Contraction A process leading to shortening and/or development of tension in muscle tissue. Muscle contraction occurs by a sliding filament mechanism whereby actin filaments slide inward among the myosin filaments. Inotropism,Muscular Contraction,Contraction, Muscle,Contraction, Muscular,Contractions, Muscle,Contractions, Muscular,Inotropisms,Muscle Contractions,Muscular Contractions
D009126 Muscle Relaxation That phase of a muscle twitch during which a muscle returns to a resting position. Muscle Relaxations,Relaxation, Muscle,Relaxations, Muscle
D009131 Muscle, Smooth, Vascular The nonstriated involuntary muscle tissue of blood vessels. Vascular Smooth Muscle,Muscle, Vascular Smooth,Muscles, Vascular Smooth,Smooth Muscle, Vascular,Smooth Muscles, Vascular,Vascular Smooth Muscles
D009213 Myography The recording of muscular movements. The apparatus is called a myograph, the record or tracing, a myogram. (From Stedman, 25th ed) Myographies
D009599 Nitroprusside A powerful vasodilator used in emergencies to lower blood pressure or to improve cardiac function. It is also an indicator for free sulfhydryl groups in proteins. Nitroferricyanide,Sodium Nitroprusside,Cyanonitrosylferrate,Ketostix,Naniprus,Nipride,Nipruton,Nitriate,Nitropress,Nitroprussiat Fides,Nitroprusside, Disodium Salt,Nitroprusside, Disodium Salt, Dihydrate,Disodium Salt Nitroprusside,Nitroprusside, Sodium
D010084 Oxidation-Reduction A chemical reaction in which an electron is transferred from one molecule to another. The electron-donating molecule is the reducing agent or reductant; the electron-accepting molecule is the oxidizing agent or oxidant. Reducing and oxidizing agents function as conjugate reductant-oxidant pairs or redox pairs (Lehninger, Principles of Biochemistry, 1982, p471). Redox,Oxidation Reduction
D011817 Rabbits A burrowing plant-eating mammal with hind limbs that are longer than its fore limbs. It belongs to the family Leporidae of the order Lagomorpha, and in contrast to hares, possesses 22 instead of 24 pairs of chromosomes. Belgian Hare,New Zealand Rabbit,New Zealand Rabbits,New Zealand White Rabbit,Rabbit,Rabbit, Domestic,Chinchilla Rabbits,NZW Rabbits,New Zealand White Rabbits,Oryctolagus cuniculus,Chinchilla Rabbit,Domestic Rabbit,Domestic Rabbits,Hare, Belgian,NZW Rabbit,Rabbit, Chinchilla,Rabbit, NZW,Rabbit, New Zealand,Rabbits, Chinchilla,Rabbits, Domestic,Rabbits, NZW,Rabbits, New Zealand,Zealand Rabbit, New,Zealand Rabbits, New,cuniculus, Oryctolagus
D003331 Coronary Vessels The veins and arteries of the HEART. Coronary Arteries,Sinus Node Artery,Coronary Veins,Arteries, Coronary,Arteries, Sinus Node,Artery, Coronary,Artery, Sinus Node,Coronary Artery,Coronary Vein,Coronary Vessel,Sinus Node Arteries,Vein, Coronary,Veins, Coronary,Vessel, Coronary,Vessels, Coronary
D004305 Dose-Response Relationship, Drug The relationship between the dose of an administered drug and the response of the organism to the drug. Dose Response Relationship, Drug,Dose-Response Relationships, Drug,Drug Dose-Response Relationship,Drug Dose-Response Relationships,Relationship, Drug Dose-Response,Relationships, Drug Dose-Response

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