ISSN:
1573-6822
Keywords:
endothelium-derived relaxing factor (EDRF)
;
methylmercury
;
platelet aggregation
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Abstract The effect of methylmercury (CH3HgCl) on the production of endothelium-derived relaxing factor (EDRF) by cultured human umbilical vascular endothelial cells (HUVECs) based on its antiaggregatory effect on human platelets was examined. HUVECs were harvested from umbilical veins by collagenase treatment. The platelet aggregation test was performed with cuvettes lined with HUVECs. Platelet aggregation induced by 0.05 units thrombin/ml was inhibited in the presence of HUVECs. This HUVEC-dependent anti-platelet aggregatory effect was enhanced by the addition of bradykinin (10 nmol/L), which stimulates the production of EDRF. Indomethacin (IND, 1 μmol/L) reduced the HUVEC-dependent anti-platelet aggregatory effect. The effect ofN G-monomethyl-L-arginine (L-NMMA, 100 μmol/L), an inhibitor of nitric oxide synthase (NOS) in endothelial cells, on HUVECs pretreated with IND showed almost complete platelet aggregation similar to results without HUVECs. The anti-platelet aggregatory effect of HUVECs pretreated with IND seemed to depend mainly on EDRF. Methylmercury (MeHg) (20–50 μmol/L) induced dose-dependent platelet aggregation in cuvettes, without HUVECs. Methylmercury (30 μmol/L) induced less platelet aggregation in the presence of HUVECs than in their absence. The degree of inhibitory effect by HUVECs on MeHg-induced platelet aggregation was reduced dose-dependently (30–50 μmol/L MeHg). Methylmercury-induced platelet aggregation at 50 μmol/L MeHg with or without HUVECs was similar. These findings suggest that this simple new experimental system is useful for assessing the production of EDRF by HUVECs, and show that MeHg inhibits the production of EDRF by HUVECs, which may be involved in the etiology of cardiovascular diseases such as hypertension and arteriosclerosis.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01305903
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