Failure of neocortical transplants to alter seizure susceptibility in previously kindled rats.

Transplantation of embryonic tissue into the brains of host animals has been demonstrated to totally or partially correct functional lesions and neurohormonal deficits in a variety of animals. This study evaluated the hypothesis that "naive" embryonic neural tissue implanted into previously kindled animals will alter subsequent seizure susceptibility. At age 16 days, male rats were electrically kindled in the right amygdala (AM). Following kindling (age 19 days), rats underwent either transplants of embryonic neocortical tissue into the left dorsal hippocampus or a sham procedure. At age 84 days, both groups underwent transfer kindling in the left AM. In addition, two other groups of 19-day-old pups that had had electrode implantation in the right AM without subsequent kindling received either embryonic neocortical implants in the left dorsal hippocampus or a sham procedure and were kindled in the left AM for the first time at age 84 days. There were no differences in rate of kindling between the animals that received successfully grafted transplants and those that underwent sham procedures. Using the kindling model, transplantation of embryonic neocortical tissue into the hippocampus does not significantly alter seizure susceptibility in the host animal.