Cerebral transplants for seizures: preliminary results

Several critical brain regions have been identified in which application of gamma-aminobutyric acid (GABA) potentiating agents in small quantities can suppress or prevent generalized and kindled amygdala seizures, i.e., substantia nigra and deep prepiriform cortex. Severity of audiogenic seizures in the genetically epilepsy prone rat (GEPR) is reduced by injection of norepinephrine (NE) into the lateral ventricles and by GABA in inferior colliculus. The present investigation examines the potential for raising epileptic thresholds by increasing local GABAergic or NE inhibitory activity by means of brain transplants of tissue rich in GABA or NE neurons. Two models of epilepsy were used: amygdala-kindled seizures and sound-induced seizures in GEPRs. Transplantation of embryonic cerebellar or cortical tissue to the deep prepiriform area of amygdala kindled rats transiently raised seizure thresholds in three of the nine animals. Transplantation of embryonic cerebellar or cortical tissue to the inferior colliculus or adrenal medulla tissue to lateral ventricles of GEPRs did not appreciably reduce the intensity of audiogenic seizures in these animals.