Effect of prolonged incubation with copper on endothelium-dependent relaxation in rat isolated aorta.
1 We investigated the effects of prolonged exposure to copper (Cu(2+)) on vascular functioning of isolated rat aorta. 2 Aortic rings were exposed to CuSO(4) (3-24 h) in Dulbecco's modified Eagle medium with or without 10% foetal bovine serum (FBS) and then challenged with vasoconstrictors or vasodilators in the absence of Cu(2+). 3 Exposure to 2 micro M Cu(2+) in the absence of FBS did not modify the response to phenylephrine (PE) or acetylcholine (ACh) in aortic rings incubated for 24 h. Identical exposure in the presence of FBS increased the contractile response to 1 micro M PE by 30% (P<0.05) and impaired the relaxant response to 3 micro M ACh or 1 micro M A23187 (ACh, from 65.7+/-7.1 to 6.2+/-1.1%, n=8; A23187, from 74.6+/-8.2 to 12.0+/-0.8%, n=6; P<0.01 for both). Cu(2+) exposure did not affect the relaxant response to NO-donors. 4 Impairment of vasorelaxation appeared 3 h after incubation with 2 micro M Cu(2+) and required 12 h to attain a steady state. Vasorelaxation to ACh was partially restored by 1 mM tiron (intracellular scavenger of superoxide ions; maximum relaxation 34.2+/-6.4%, n=10, P<0.01 vs Cu(2+) alone), whereas catalase, superoxide dismutase or cycloheximide were ineffective. 5 Twenty-four hour-exposure to 2 micro M Cu(2+) did not affect endothelium integrity or eNOS expression, and increased the Cu content in arterial rings from 6.8+/-1.1 to 18.9+/-2.9 ng mg(-1) wet weight, n=8; P<0.01. 6 Our results show that, in the presence of FBS, prolonged exposure to submicromolar concentrations of Cu(2+) impaired endothelium-dependent vasorelaxation in aortic rings, probably through an intracellular generation of superoxide ions. British Journal of Pharmacology (2002) 136, 1185-1193
Chiarugi
Alberto
A
Stroke and Neurovascular Regulation Laboratory, Department of Neuroscience, Harvard Medical School, Massachusetts General Hospital, 149 13th Street, Charlestown 02129, USA.
Pitari
Giovanni Mario
GM
Costa
Rosa
R
Ferrante
Margherita
M
Villari
Loredana
L
Amico-Roxas
Matilde
M
Godfraind
Théophile
T
Bianchi
Alfredo
A
Salomone
Salvatore
S
D000818:Animals; D001011:Aorta / Q000187:drug effects / Q000378:metabolism / Q000502:physiology; D019327:Copper Sulfate / Q000494:pharmacology*; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D006801:Humans; D006836:Hydro-Lyases / Q000378:metabolism; D066298:In Vitro Techniques; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D019001:Nitric Oxide Synthase / Q000378:metabolism; D052250:Nitric Oxide Synthase Type III; D010656:Phenylephrine / Q000494:pharmacology; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors; D014471:Umbilical Veins / Q000378:metabolism; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D014664:Vasodilation / Q000187:drug effects*; D014665:Vasodilator Agents / Q000494:pharmacology*
D019408:Platelet Endothelial Cell Adhesion Molecule-1; D014662:Vasoconstrictor Agents; D014665:Vasodilator Agents; D010656:Phenylephrine; C496314:NOS3 protein, human; D019001:Nitric Oxide Synthase; D052250:Nitric Oxide Synthase Type III; C496316:Nos3 protein, rat; D006836:Hydro-Lyases; C045581:lactate dehydratase; D019327:Copper Sulfate