A single neonatal pentylenetetrazol or hyperthermia convulsion increases kindling susceptibility in the adult rat.

Convulsions were induced in young rats (1-21 days) with pentylenetetrazol or hyperthermia. As adults, these animals were kindled electrically in the basolateral or cortical amygdala, the hippocampus, or the pyriform cortex. Fewer amygdala stimulations were required to evoke major motor seizures in subjects treated at 1, but not at 10 or 21 days of age. No further facilitation in kindling rate was observed in subjects receiving 3 convulsions on days 1, 3 and 5 or 1, 5 and 9. This facilitation of electrical kindling was limited to the amygdaloid sites. The results could not be attributed to gross brain damage or differential convulsion histories. This age-limited, structure-specific effect suggests that the amygdala may represent a unique seizure-generating system in the brain that is sensitive to neural alteration at particular times during development.