The anticonvulsant activity of ketamine agains siezures induced by pentylenetetrazol and mercaptopropionic acid.

The activity of the dissociative anaesthetics ketamine and gamma-hydroxybutyrate against seizures induced by mercaptopropionate and pentylenetetrazol have been determined. Ketamine (90 mg/kg) prevented the seizures induced by both convulsants, but gamma-hydroxybutyrate had negligible anticonvulsant activity. Mercaptopropionate (150 mg/kg) produced a rapid fall in whole brain glutamate decarboxylase activity which correlated with the onset of convulsions. Ketamine given prior to the mercaptopropionate prevented the convulsions, but had no effect on the reduction of enzyme activity. It was concluded that although ketamine was an anticonvulsant it did not act by preventing the inhibition of glutamate decarboxylase responsible for mercaptopropionate-induced convulsions.