[Drug-induced seizures in taurine-deficient mice]

Appearances of pentetrazole-, picrotoxin- and strychnine-induced convulsive seizures in taurine-deficient mice produced by treatment with guanidinoethyl sulfonate (GES), a taurine transport antagonist, were investigated. Mice were fed a taurine-free diet and water containing 1% GES from 2 weeks of pregnancy to weaning. The same feeding condition was applied to male offsprings from 3 weeks of age. At 5 weeks of age, convulsants were administered to some mice and the others were sacrificed for determination of brain amino acids concentrations. The incidences of both seizure and death for strychnine and death for picrotoxin were enhanced by treatment with GES, whereas the latency of pentetrazole-induced tonic extensor was prolonged. Significant decrease of brain taurine, asparaginic acid and GABA concentrations were observed in mice treated with GES. These results suggest that convulsive seizures caused by disinhibition of taurine and GABA system are enhanced by deficiency of brain taurine level.