Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
6022064 | Neurobiology of Disease | 2014 | 10 Pages |
Abstract
Prolonged hypoxia leads to irreversible loss of neuronal function and metabolic impairment of nicotinamide adenine dinucleotide recycling (between NADÂ + 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 NADÂ +) 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 3Â min 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 (5Â mM) 2Â h 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 (>Â 1Â h) 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.
Keywords
fEPSPPARP-1CA1ROIaCSFSIRT-1HSDNAD(H)NAD+ROSstratum radiatumcornu ammonis region 1AIFReoxygenationdentate gyrusapoptosis-inducing factorartificial cerebrospinal fluidBrainregion of interestNAMNAD, nicotinamide adenine dinucleotideNicotinamideHippocampusHypoxiafield excitatory post-synaptic potentialPoly(ADP-ribose) polymerase-1TCA cycletricarboxylic acid cycleSpreading depressionReactive oxygen species
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Authors
Pavan K. Shetty, Francesca Galeffi, Dennis A. Turner,