Despite the internucleosomal cleavage of DNA, reactive oxygen species do not produce other markers of apoptosis in cultured neurons

The cell death induced by hydroxyl radicals generated by Cu-phenanthroline and peroxynitrite generated by 3-morpholinosydnonimine hydrochloride (SIN-1 ) in rat primary cortical neuronal cultures was compared with the apoptotic death induced by staurosporine and the necrotic death induced by glutamate , Both SIN-1 and Cu-phenanthroline were capable of generating internucleoso mal cleavage of DNA-a hallmark of apoptosis. Other characteristics of this cell death, such as nuclear morphology by light microscopy; DNA breaks by s ingle-cell gel electrophoresis; the effects of the apoptotic inhibitors cyc loheximide, aurintricarboxylic acid, and tosyl-L-lysine chloromethyl ketone ; the measurement of caspase activity; and the effects of antioxidants, wer e then analyzed. The conclusion from these hallmarks of apoptosis is that t he cell death induced by these reactive oxygen species is not apoptosis. (C ) 2000 Academic Press.