title: Nicotinamide pre-treatment ameliorates NAD(H) hyperoxidation and improves neuronal function after severe hypoxia.
abstract: Prolonged hypoxia leads to irreversible loss of neuronal function and metabolic impairment of nicotinamide adenine dinucleotide recycling (between NAD(+) and NADH) immediately after reoxygenation, resulting in NADH hyperoxidation. We test whether the addition of nicotinamide (to enhance NAD(+) levels) or PARP-1 inhibition (to prevent consumption of NAD(+)) can be effective in improving either loss of neuronal function or hyperoxidation following severe hypoxic injury in hippocampal slices. After severe, prolonged hypoxia (maintained for 3min after spreading depression) there was hyperoxidation of NADH following reoxygenation, an increased soluble NAD(+)/NADH ratio, loss of neuronal field excitatory post-synaptic potential (fEPSP) and decreased ATP content. Nicotinamide incubation (5mM) 2h prior to hypoxia significantly increased total NAD(H) content, improved neuronal recovery, enhanced ATP content, and prevented NADH hyperoxidation. The nicotinamide-induced increase in total soluble NAD(H) was more significant in the cytosolic compartment than within mitochondria. Prolonged incubation with PJ-34 (>1h) led to enhanced baseline NADH fluorescence prior to hypoxia, as well as improved neuronal recovery, NADH hyperoxidation and ATP content on recovery from severe hypoxia and reoxygenation. In this acute model of severe neuronal dysfunction prolonged incubation with either nicotinamide or PJ-34 prior to hypoxia improved recovery of neuronal function, enhanced NADH reduction and ATP content, but neither treatment restored function when administered during or after prolonged hypoxia and reoxygenation.
authors.affiliation: Neurosurgery and Neurobiology, Duke University Medical Center, Research and Surgery Services, Durham VAMC, NC 27710, USA. Electronic address: shetty.p@duke.edu.
authors.forename: Pavan K
authors.initials: PK
authors.lastname: Shetty
authors.affiliation: Neurosurgery and Neurobiology, Duke University Medical Center, Research and Surgery Services, Durham VAMC, NC 27710, USA.
authors.forename: Francesca
authors.initials: F
authors.lastname: Galeffi
authors.affiliation: Neurosurgery and Neurobiology, Duke University Medical Center, Research and Surgery Services, Durham VAMC, NC 27710, USA.
authors.forename: Dennis A
authors.initials: DA
authors.lastname: Turner
mesh_terms: D000255:Adenosine Triphosphate / Q000032:analysis / Q000378:metabolism; D000818:Animals; D006624:Hippocampus / Q000187:drug effects / Q000378:metabolism* / Q000503:physiopathology; D002534:Hypoxia, Brain / Q000188:drug therapy* / Q000378:metabolism; D066298:In Vitro Techniques; D008297:Male; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism; D009243:NAD / Q000032:analysis / Q000378:metabolism*; D009474:Neurons / Q000187:drug effects / Q000502:physiology; D018696:Neuroprotective Agents / Q000627:therapeutic use*; D009536:Niacinamide / Q000627:therapeutic use*; D051381:Rats; D011916:Rats, Inbred F344
chemical_list: D018696:Neuroprotective Agents; D009243:NAD; D009536:Niacinamide; D000255:Adenosine Triphosphate
keywords: ACSF; AIF; Brain; CA1; DG; H; HSD; Hippocampus; Hypoxia; NAD(+); NAD(H); NAM; Nicotinamide; PARP-1; ROI; ROS; SIRT-1; SR; Spreading depression; TCA cycle; apoptosis-inducing factor; artificial cerebrospinal fluid; cornu ammonis region 1; dentate gyrus; fEPSP; field excitatory post-synaptic potential; hypoxia; hypoxic spreading depression; nicotinamide; nicotinamide adenine dinucleotide; poly(ADP-ribose) polymerase-1; reactive oxygen species; region of interest; reox; reoxygenation; silent mating-type information regulation 1; stratum radiatum; total NAD(+) and NADH content; tricarboxylic acid cycle