Two type of aggregate in the cerebral cortex of a seizure-sensitive strainof the Mongolian gerbil

A 70-kDa protein, P70, found mostly in the pyramidal cells of the cerebral cortex of cobalt-induced epileptogenic rats, has been-implicated in epilept ogenesis. The presence of a P70-like substance was searched for immunohisto chemically in the cerebral cortex of MGS/ldr, a seizure-sensitive strain of the Mongolian gerbil (Meriones unguiculatus) that we previously establishe d. Immunoreactive aggregates were observed in the pyramidal neurons of the motor cortex and the primary somatosensory cortex. Analysis using confocal laser:scanning microscopy revealed that the aggregates were often colocaliz ed with a second type of aggregate with red autofluorescence at the margina l zone of the cell somata. Both aggregates appeared and increased before th e appearance of generalized tonic-clonic convulsion. These may be involved in some change of physiological function of the cerebral cortex but their p resence itself is not enough to determine the occurrence of epileptic seizu re because the gerbils that showed no such seizure had both aggregates. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.