title: The nitric oxide donor NOC12 protects cultured astrocytes against apoptosis via a cGMP-dependent mechanism.
abstract: We examined the effect of 3-ethyl-3-(ethylaminoethyl)-1-hydroxy-2-oxo-1-triazene (NOC12), a nitric oxide (NO) donor, on apoptosis in cultured astrocytes. Reperfusion after hydrogen peroxide (H2O2) exposure caused a decrease in cell viability, loss of mitochondrial membrane potential, caspase-3 activation, DNA ladder formation, and nuclear condensation. NOC12 at 10-100 microM significantly attenuated these apoptotic changes, while the NO donor at 1 mM caused cell injury and exacerbated the H202-induced cell injury. NOC12 increased intracellular cGMP levels in a dose dependent manner with the maximal effect at 100 microM. The protective effect of NOC12 was mimicked by the NO-independent guanylate cyclase activator 3-(5'-hydroxymethyl-2'-furyl)-1-benzyl indazole, and was attenuated by the guanylate cyclase inhibitor 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ) and the cGMP-dependent protein kinase inhibitor KT5823. ODQ and KT5823 did not block but rather exacerbated the cytotoxic effect of NOC12 at 1 mM. These findings demonstrate that lower concentrations of NOC12 inhibit the H2O2-induced apoptosis of astrocytes in a cGMP-dependent way, but higher concentrations of NOC12 show a toxic effect on astrocytes in a cGMP-independent way.
authors.affiliation: Department of Analytical Chemistry, Faculty of Pharmaceutical Sciences and High Technology Research Center, Kobe Gakuin University, Kobe, Japan.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Takuma
authors.forename: Patamawan
authors.initials: P
authors.lastname: Phuagphong
authors.forename: Eibai
authors.initials: E
authors.lastname: Lee
authors.forename: Riyo
authors.initials: R
authors.lastname: Enomoto
authors.forename: Koichi
authors.initials: K
authors.lastname: Mori
authors.forename: Akemichi
authors.initials: A
authors.lastname: Baba
authors.forename: Toshio
authors.initials: T
authors.lastname: Matsuda
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D001253:Astrocytes / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D006152:Cyclic GMP / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation; D006861:Hydrogen Peroxide / Q000494:pharmacology; D008564:Membrane Potentials / Q000187:drug effects; D008928:Mitochondria / Q000187:drug effects / Q000502:physiology; D009569:Nitric Oxide / Q000502:physiology; D020030:Nitric Oxide Donors / Q000494:pharmacology*; D009603:Nitroso Compounds / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar
chemical_list: C118603:NOC 12; D020030:Nitric Oxide Donors; D009603:Nitroso Compounds; D009569:Nitric Oxide; D006861:Hydrogen Peroxide; C505410:Casp3 protein, rat; D053148:Caspase 3; D020169:Caspases; D006152:Cyclic GMP