Suppression and induction of epileptic activity by neuronal grafts.

Fetal rat brain cell suspensions prepared from either the locus coeruleus region or hippocampus were implanted bilaterally into the subcortically denervated seizure-prone hippocampus of adult rats. Animals with locus coeruleus grafts were protected against picrotoxin-induced behavioral seizures and had significantly fewer interictal spikes. In contrast, in rats with fetal hippocampal grafts the incidence of interictal spikes was significantly higher than in lesion-only controls, and spontaneous behavioral seizures occurred in almost half of the animals. We suggest that neuronal grafting offers an alternative method for studying the mechanisms and control of epileptic brain activity.