Neither the DNA damage pathway nor the cGMP-dependent pathway is involved in cell vulnerability toward NO. (A) Comparison between MIN6 cells and RAW 264.7 cells in cell viability and production of 8-hydroxy-2′-deoxyguanosine 48 h after treatment with various concentrations of SNAP (mean ± SE, n = 3). (B) Effects of SNAP on mRNAs for p53, p21, and GADD45 in MIN6 cells. RNAs were prepared 6 h after treatment. TG, thapsigargin (2 μM); CPT, camptothecin (a DNA-damaging agent) (100 nM). (C) Effects of 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ) (10 μM) and KT-5823 (300 μM) on NO-dependent apoptosis in MIN6 cells and effects of 8-bromo cGMP on cell proliferation. 1H-[1,2,4]Oxadiazolo[4,3-a]quinoxalin-1-one and KT-5823 were added 30 min before exposure to SNAP. Cell viability and cell number were assayed 48 h after treatment (mean ± SE, n = 3).