Transplantation in Experimental Epilepsy

Epileptic seizures are characterized by hyperexcitability and synchrony among populations of central neurons, but the mechanisms underlying the abnormal patterns of electric activity are only partly known. There is evidence from human autopsy material that the increased excitability results from a loss of inhibitory, presumably GABA-ergic, neurons (GABA, γ-aminobutyric acid). Possibly the hyper-excitability also depends on an abnormal increase of excitatory synaptic mechanisms. Finally, at least in experimental animals, some long-loop neuronal circuitries might be able to influence the development and generalization of epileptiform activity; for example, the noradrenergic locus ceruleus system, which originates in the pons and has widespread projections to almost the entire CNS, dampens seizures in the brain.