Establishment of status epilepticus by limbic system stimulation in previously unstimulated rats

A syndrome of convulsive status epilepticus developed in 4 of 18 rats which had been treated with continuous sine wave stimulation incrementally raised to 40 microA through limbic system electrodes. The syndrome was characterized by recurrent behavioral seizures, continuous EEG spiking, and marked neuropathology. In three other animals, the stimulation treatment produced a syndrome of nonconvulsive status epilepticus manifested by an electrophysiologic record of continuous seizure activity, without accompanying tonic-clonic movements. The poststimulatory effect was correlated with the animals' response to the stimulation, and was independent of whether the electrode was positioned in the hippocampus or amygdala. If an animal developed repeated convulsive seizures during the stimulation, such seizures were likely to persist after the stimulation offset. These results indicate that persistent limbic system activation can produce a syndrome of recurrent seizures similar to that caused by either neurotoxic drugs or by limbic system activation in kindled rats.