The polysialic acid modification of the neural cell adhesion molecule is involved in spatial learning and hippocampal long-term potentiation

✍ Scribed by C.G. Becker; A. Artola; R. Gerardy-Schahn; T. Becker; H. Welzl; M. Schachner

• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: English
• Weight: 959 KB
• Volume: 45
• Category: Article
• ISSN: 0360-4012
• DOI: 10.1002/(sici)1097-4547(19960715)45:2<143::aid-jnr6>3.0.co;2-a

✦ Synopsis

The a-2,Slinked polysialic acid (PSA) modification of the neural cell adhesion molecule (NCAM) modulates morphogenetic cell interactions. PSA is strongly expressed during neural development and generally down-regulated in the adult. However, it remains prominent in some areas of the brain, e.g., the hippocampus. We assayed the functional role@) of PSA in synaptic plasticity in the hippocampus in two experimental paradigms by removing PSA with endoneuraminidase NE (endo-N) an enzyme which specifically cleaves a-2,S-linked polysialic acid. (1) The acquisition and retention of spatial memory of rats in the Morris water maze, critically dependent on the hippocampus, was significantly impaired after a lo- calized injection of endo-N into the hippocampus, whereas visual and motor capacities were unaffected.

(2) Tetanic stimulation of the Schaffer collaterals in endo-N-treated hippocampal slices in vitro failed to elicit LTP and yielded only a short post-tetanic potentiation, but the response returned to control levels within 2 minutes, whereas basal synaptic activity and short-term potentiation were not affected. Our findings suggest that the carbohydrate epitope PSA plays an important role in synaptic plasticity.