Abstract
A Corrigendum has been published for this article in Redox Report, Volume 17, Number 1, January 2012, page 47: http://www.ingentaconnect.com/content/maney/rer/2012/00000017/00000001/art00006 (please copy and paste this URL into your web browser in order to link to it)This present study examined the effects of high concentrations of nitric oxide (NO•) and peroxynitrite (ONOO-) on superoxide (O2•-) production from formyl-methionyl-leucyl-phenylalanine (fMLP)-stimulated polymorphonuclear leukocytes (PMNs) by using electron spin resonance (ESR) and spin trapping with 5-(diethoxyphosphoryl)-5-methyl-1-pyrroline-N-oxide (DEPMPO). We demonstrated that ONOO- (100 μM) decreased the ESR signal of DEPMPO-OOH from fMLP-activated PMNs, indicating the inhibition of O2•- generation, while it enhanced the signal of DEPMPO-OH. Inhibition of the respiratory burst was also observed when PMNs were pre-exposed to high concentrations of NO• (100 μM), generated by the NO• donor NOR-1, 30 min prior to stimulation with fMLP. NOR-1 inhibited O2•- generation more effectively under conditions in which ONOO- was formed concurrently. The ability of high concentrations of either ONOO- or NO• to inhibit O2•- generation from fMLP-stimulated PMNs is relevant to pathophysiological conditions, such as severe inflammation, in which NO• or ONOO- production can be significantly elevated.