Neuronal survival and DNA fragmentation were assessed by trypan blue dye exclusion (TB) and TUNEL 24 hours following exposure to a NO donor (NOC-9 or SNP, 300 μM). The mGluRI agonist (DHPG, 750 μM) or antagonist (AIDA, 750 μM) was applied 1 hour prior to NO exposure. (A) Representative images illustrate that cultures with NO exposure were stained with TB and TUNEL. Application of DHPG significantly reduced TB staining and TUNEL labeling during NO exposure. (B) Application of DHPG (750 μM), but not AIDA, 1 hour prior to NO significantly increased neuronal survival 24 hours following NO exposure (*P<0.01 vs. NO treated alone). (C) DHPG, applied 1 hour prior to NO exposure significantly reduced DNA fragmentation 24 hours following NO exposure (*P<0.01 vs. NO treated alone). In B and C, to simplify the figures, the results for the two NO donors were combined. Each data point represents the mean ± SEM.