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Endothelial dysfunction of rat coronary arteries after exposure to low concentrations of mercury is dependent on reactive oxygen species
Author(s) -
Furieri Lorena B,
Galán María,
Avendaño María S,
GarcíaRedondo Ana B,
Aguado Andrea,
Martínez Sonia,
Cachofeiro Victoria,
Bartolomé M Visitación,
Alonso María J,
Vassallo Dalton V,
Salaices Mercedes
Publication year - 2011
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.2011.01203.x
Subject(s) - medicine , vasodilation , coronary perfusion pressure , vasoconstriction , coronary arteries , superoxide , nitric oxide , chemistry , endothelial dysfunction , cardiology , myograph , endocrinology , blood pressure , perfusion , acetylcholine , artery , anesthesia , biochemistry , cardiopulmonary resuscitation , resuscitation , enzyme
BACKGROUND AND PURPOSE Exposure to mercury is known to increase cardiovascular risk but the underlying mechanisms are not well explored. We analysed whether chronic exposure to low mercury doses affects endothelial modulation of the coronary circulation. EXPERIMENTAL APPROACH Left coronary arteries and hearts from Wistar rats treated with either HgCl 2 (first dose 4.6 µg·kg −1 , subsequent doses 0.07 µg·kg −1 day −1 , 30 days) or vehicle were used. Endothelial cells from pig coronary arteries incubated with HgCl 2 were also used. KEY RESULTS Mercury treatment increased 5‐HT‐induced vasoconstriction but reduced acetylcholine‐induced vasodilatation. It also reduced nitric oxide (NO) production and the effects of NO synthase inhibition with L‐NAME (100 µmol·L −1 ) on 5‐HT and acetylcholine responses. Superoxide anion production and mRNA levels of NOX‐1 and NOX‐4 were all increased. The superoxide anion scavenger tiron (1 mmol·L −1 ) reduced 5‐HT responses and increased acetylcholine responses only in vessels from mercury‐treated rats. In isolated hearts from mercury‐treated rats, coronary perfusion and diastolic pressure were unchanged, but developed isovolumetric systolic pressure was reduced. In these hearts, L‐NAME increased coronary perfusion pressure and diastolic pressure while it further reduced developed systolic pressure. CONCLUSIONS AND IMPLICATIONS Chronic exposure to low doses of mercury promotes endothelial dysfunction of coronary arteries, as shown by decreased NO bioavailability induced by increased oxidative stress. These effects on coronary function increase resistance to flow, which under overload conditions might cause ventricular contraction and relaxation impairment. These findings provide further evidence that mercury, even at low doses, could be an environmental risk factor for cardiovascular disease.