title: Impairment of long-term potentiation and associative memory in mice that overexpress extracellular superoxide dismutase.
abstract: Reactive oxygen species, including superoxide, generally are considered neurotoxic molecules whose effects can be alleviated by antioxidants. Different from this view, we show that scavenging of superoxide with an antioxidant enzyme is associated with deficits in hippocampal long-term potentiation (LTP), a putative neural substrate of memory, and hippocampal-mediated memory function. Using transgenic mice that overexpress extracellular superoxide dismutase (EC-SOD), a superoxide scavenger, we found that LTP was impaired in hippocampal area CA1 despite normal LTP in area CA3. The LTP impairment in area CA1 could be reversed by inhibition of EC-SOD. In addition, we found that EC-SOD transgenic mice exhibited impaired long-term memory of fear conditioning to contextual cues despite exhibiting normal short-term memory of the conditioning experience. These findings strongly suggest that superoxide, rather than being considered exclusively a neurotoxic molecule, should also be considered a signaling molecule necessary for normal neuronal function.
authors.affiliation: Department of Neuroscience and Center for the Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA.
authors.forename: E
authors.initials: E
authors.lastname: Thiels
authors.forename: N N
authors.initials: NN
authors.lastname: Urban
authors.forename: G R
authors.initials: GR
authors.lastname: Gonzalez-Burgos
authors.forename: B I
authors.initials: BI
authors.lastname: Kanterewicz
authors.forename: G
authors.initials: G
authors.lastname: Barrionuevo
authors.forename: C T
authors.initials: CT
authors.lastname: Chu
authors.forename: T D
authors.initials: TD
authors.lastname: Oury
authors.forename: E
authors.initials: E
authors.lastname: Klann
mesh_terms: D000818:Animals; D001245:Association Learning; D001362:Avoidance Learning; D003463:Cues; D019706:Excitatory Postsynaptic Potentials / Q000502:physiology; D005110:Extracellular Space / Q000201:enzymology*; D005239:Fear; D006579:Heterozygote; D006624:Hippocampus / Q000166:cytology / Q000378:metabolism / Q000503:physiopathology; D006801:Humans; D066298:In Vitro Techniques; D017774:Long-Term Potentiation / Q000235:genetics; D008297:Male; D008569:Memory Disorders / Q000235:genetics* / Q000503:physiopathology; D051379:Mice; D008822:Mice, Transgenic; D017288:Pain Threshold; D018408:Patch-Clamp Techniques; D017382:Reactive Oxygen Species / Q000378:metabolism; D015398:Signal Transduction; D013037:Spatial Behavior; D013482:Superoxide Dismutase / Q000096:biosynthesis* / Q000235:genetics; D009435:Synaptic Transmission / Q000235:genetics
chemical_list: D017382:Reactive Oxygen Species; D013482:Superoxide Dismutase