Epilepsy-like convulsive seizures induced by cholera toxin administration into amygdaloid complex and lateral...

Epilepsy-like convulsive seizures have been induced by cholera toxin administration into the rat amygdaloid complex and lateral ventricle. Between the 8th and 48th h following the administration, rhythmic spike discharges (1-3 spikes/s) were electroencephalographically observed bilaterally in the amygdaloid complexes, and rats exhibited abnormal behaviors such as running, jumping, tail lifting, rearing, vocalization, aggressive behavior, facial twitching and increased salivation. During these stages, high voltage spikes were intermittently observed with generalized convulsive seizures. Duration of the seizure was 1-2 min and the incidence was 0-6 times/h. At 48 h after the administration or thereafter, convulsive seizures disappeared and electroencephalographic abnormalities were gradually normalized. Occasional rhythmic spike discharges, however, were observed more than 168 h after the administration. Intraventricularly administered cholera toxin also induced the same type of convulsive seizures. Cyclic AMP content in the rat cerebrum from toxin-treated animals was significantly higher than that found in controls. The present results clearly indicate that cholera toxin administered intraventricularly as well as into the amygdaloid complexes of the rats induces epileptic attack-like convulsive seizures 8-48 h after the administration and this effect of the toxin is most likely to be related to the increase of cerebral cyclic AMP content.