INCREASED DENTATE GRANULE CELL NEUROGENESIS FOLLOWING AMYGDALA KINDLING IN THE ADULT-RAT

Structural neuronal network plasticity is associated with epileptogene sis during limbic kindling, but the full extent of network changes is not well understood. We investigated whether dentate granule cell (DGC ) neurogenesis, which continues into adulthood in the rodent, is alter ed in the amygdala kindling model of epileptogenesis. Adult rats were stimulated to either 4-6, 9-10 or 19-20 class 4/5 (generalized) kindle d seizures. 5-Bromo-2'-deoxyuridine labeling showed that cell prolifer ation increased in the dentate gyrus only in animals that experienced nine or more class 4/5 kindled seizures. Immunocytochemistry for neuro nal markers revealed that many of the newly generated cells differenti ated into DGCs in the inner aspect of the DGC layer. The lack of incre ased DGC neurogenesis after fewer kindled seizures or at early timepoi nts following kindling suggests that this process is not involved in k indling development. Instead, newly generated DGCs may be important fo r maintenance of the kindled state or the increased susceptibility to spontaneous recurrent seizures. (C) 1998 Elsevier Science Ireland Ltd.