Molecular overexpression of extracellular superoxide dismutase increases the dependency of learning and memory performance on motivational state.

Journal Article

Extracellular superoxide dismutase (EC-SOD) controls the availability of extracellular superoxide and appears to play a role in controlling intercellular signaling. In this role EC-SOD can have potent effects on neurobehavioral function. In previous studies, we have found that either over- or under-expression of EC-SOD in mice significantly impairs spatial learning on the radial-arm maze. In the current study, the neurobehavioral nature of the EC-SOD role in cognitive function was determined. EC-SOD overexpression altered the relationship between both learning and memory with motivational state. Mice were tested in the radial-arm maze under a high motivational state (22-24 hours of food restriction) or a low motivational state (4-6 hours of food restriction). Under a high motivational state, the EC-SOD overexpressing mice were able to learn in the radial-arm maze, albeit at a slightly lower rate than wild-type controls. This contrasts with the failure to learn by EC-SOD overexpressing mice in our previous study conducted with the low motivational state. The change in motivational state did not significantly alter the learning rate of controls. Similarly, during postacquisition memory phase of testing, the EC-SOD overexpressing mice were significantly worse than controls when tested in a low motivational state but not under a high motivation state. As with learning, motivational state did not significantly affect memory performance in controls. This study shows that mice with EC-SOD overexpression are not incapable of learning and memory in the radial-arm maze, but that the mechanisms which allow control animals to perform this task well under low motivational states are deficient in the mice with EC-SOD overexpression.

Full Text

Duke Authors

Cited Authors

  • Levin, ED; Brucato, FH; Crapo, JD

Published Date

  • March 2000

Published In

Volume / Issue

  • 30 / 2

Start / End Page

  • 95 - 100

PubMed ID

  • 10979599

Pubmed Central ID

  • 10979599

International Standard Serial Number (ISSN)

  • 0001-8244

Digital Object Identifier (DOI)

  • 10.1023/a:1001947003299


  • eng

Conference Location

  • United States