ISSN:
1573-3297
Keywords:
Extracellular superoxide dismutase
;
SOD
;
memory
;
learning
;
radial-arm maze
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Psychology
Notes:
Abstract Extracellular superoxide dismutase (EC-SOD) controls the availability of extracellular superoxide (O 2 - ), which is important for a variety of physiological pathways, including the primary means of inactivating nitric oxide (NO). The role of EC-SOD in neurobehavioral function has been until now unexplored. In the current studies, the phenotypic expression of genotypic alterations of EC-SOD production in mice were characterized for spatial learning and memory. Dramatic impairments in spatial learning in the win-shift 8-arm radial maze were seen in both EC-SOD knockout mice and EC-SOD overexpressing mice. The EC-SOD overexpressing mice were further characterized as having significant deficits in a repeated acquisition task in the radial-arm maze, which permitted the dissociation of long and short-term learning. Long-term learning was significantly impaired by EC-SOD overexpression, whereas short-term learning was not significantly affected by EC-SOD overexpression. NO systems have been shown to be importantly involved in learning and memory. This may be important in the current studies because EC-SOD has primary control over the inactivation of NO. We found that EC-SOD overexpressing mice were resistant to the cognitive effects of L-NAME (NG-nitro-L-arginine methyl ester hydrochloride), an NO synthase inhibitor. Decreased NO catabolism in these mice may have served to counter the effects of NOS inhibition by L-NAME. The current finding that EC-SOD levels that were either higher or lower than controls impaired learning demonstrates that the proper control of brain extracellular (O 2 - ) may be more vital than merely reduction of brain extracelluar (O 2 - ) in maintaining adequate learning function.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1021673703129
Permalink