Afterdischarge threshold reduction in the kindling model of epilepsy.

Female Wistar rats were implanted with electrodes in the right amygdala, and initial--pre-kindling--afterdischarge thresholds (ADT's) were determined 1, 2, 4, and 8 weeks after electrode implantation. Pre-kindling ADT's were highest 1 week after implantation, lower at 2 weeks, and lowest at 4 weeks. This drop in non-stimulated thresholds had largely disappeared by 8 weeks post-implantation. Half of each group was then kindled, while the other half was "sham" kindled. ADTs were re-measured 1 week after the 10th Stage 5 seizure. When kindling was begun 1 or 2 weeks after implantation (when non-stimulated thresholds were dropping), no effect of kindling on ADT's could be seen. When kindling was begun 4 or 8 weeks after implantation (when non-stimulated thresholds were rising), however, kindling clearly lowered thresholds.