Free-radical scavengers, thiol-containing reagents and endothelium-dependent relaxation in isolated rat and human resistance arteries
| Autor: | PS Sever, A.D. Hughes, W. Sunman |
|---|---|
| Rok vydání: | 1993 |
| Předmět: |
Male
medicine.medical_specialty Captopril Vascular smooth muscle Endothelium Pharmacology Arginine Muscle Smooth Vascular Rats Sprague-Dawley Superoxide dismutase Norepinephrine chemistry.chemical_compound Isometric Contraction Internal medicine medicine Animals Humans Dose-Response Relationship Drug biology Superoxide Dismutase Superoxide Drug Synergism Arteries General Medicine Catalase Acetylcholine Acetylcysteine Rats NG-Nitroarginine Methyl Ester Endocrinology medicine.anatomical_structure chemistry biology.protein Female Vascular Resistance Endothelium Vascular Blood vessel Myograph medicine.drug |
| Zdroj: | Clinical Science. 84:287-295 |
| ISSN: | 1470-8736 0143-5221 |
| DOI: | 10.1042/cs0840287 |
| Popis: | 1. Small arteries were isolated from either rat mesentery or human subcutaneous fat, and mounted in a myograph for the measurement of isometric force. 2. Superoxide dismutase, either in the presence or absence of catalase, relaxed noradrenaline-induced tone. This effect was abolished by removal of the endothelium or incubation with an inhibitor of NO synthase, N-ω-nitro-L-arginine methyl ester. Catalase alone had a negligible effect on noradrenaline-induced tone. 3. Captopril, an angiotensin-converting enzyme inhibitor and putative free-radical scavenger, did not relax pre-contracted isolated vessels. N-Acetylcysteine caused an endothelium-independent relaxation of rat vessels. Similar effects were observed in human vessels. 4. Acetylcholine induced a concentration-dependent relaxation of isolated resistance arteries, which was inhibited by removal of the endothelium or N-ω-nitro-L-arginine methyl ester, but unaffected by indomethacin. Preincubation with captopril, N-acetylcysteine or catalase alone did not alter the acetylcholine concentration-response relationship, but superoxide dismutase in combination with catalase enhanced responses to acetylcholine, causing a six-fold increase in potency. 5. Superoxide dismutase causes endothelium-dependent relaxation of resistance arteries and potentiates responses to acetylcholine. This action is probably due to the ability of the enzyme to scavenge superoxide anions which inhibit endothelium-dependent relaxation. 6. N-Acetylcysteine causes an endothelium-independent relaxation of resistance arteries which is probably unrelated to the putative ability of this compound to scavenge superoxide radicals and may reflect a direct action on vascular smooth muscle. |
| Databáze: | OpenAIRE |
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