<正> Objective: To examine the role of p38 mitogen-activated protein kinase （MAPK） in NO production and iNOS expression in human endothelial cells stimulated by lipopolysaccharide （LPS）. Methods: The NO level in the supernatant of the cell culture media was measured with Griess method

expressions of iNOS protein and mRNA in vitro cultured endothelial cell line ECV304 were detected with immunofluorescence analysis and reverse transcriptase-PCR respectively. Immunokinase assay was employed to measure p38 MAPK activity. Results: Compared with the basal level of iNOS expression and NO production

the NO level and the expressions of iNOS mRNA and protein in the cells were increased after LPS stimulation. p38 MAPK activity in ECV304 cells exhibited a marked increase at 15 min after LPS stimulation

lasting for about 45 min before gradually decline. The iNOS protein and mRNA expressions induced by LPS stimulation was significantly inhibited by SB203580 [4-（4-fluorophenyl）-2-（4- methylsulfinylphenyl）-5-（4-pyridyl）