Highly polysialylated neural cell adhesion molecule (PSA-NCAM) positive cells are increased and change localization in rat hippocampus by exposure to repeated kindled seizures

The highly polysialylated neural cell adhesion molecule (PSA-NCAM) is involved in migration of neural stem cells as well as in neural plasticity. Immunoreactivc PSA-NCAM expression was examined in rats with repeated exposure to amygdaloid kindled generalized seizures (GS). The number of PSA-NCAM positive cells in the bilateral dentate gyrus (DG) increased significantly from GS. Although the total number of positive cells was not significantly different between animals with 3 times GS (3 GS) and 30 times GS (30 GS), in the latter group a greater number of positive cells was observed in the outer granule cell layer (GCL) and a marked extension of immunopositive dendrites to the molecular layer. These observations indicate that increased migration of newly generated cells as well as plastic changes of preexisting neural cells occur in response to recurrent GS. This may contribute to an abnormal reconstruction of the synaptic network in the hippocampus and, thus, epileptogenicity from kindling.