Cerebral glutamic acid decarboxylase activity and gamma-aminobutyric acid concentrations in mice susceptible or resistant to audiogenic seizures.

DBA/2 mice between 21 and 28 days of age are highly susceptible to sound-induced seizures. Drug studies suggest a possible deficit of gamma-aminobutyric acid (GABA)-mediated neurotransmission may be involved. We have measured the whole brain GABA concentration and glutamic acid decarboxylase activity in DBA/2 mice at various ages before, during, and after the period of maximal susceptibility to audiogenic seizures. Corresponding determinations were carried out on age-matched TO mice, a strain much less susceptible to audiogenic seizures than DBA/2 mice at all ages. No significant differences in GABA concentration or glutamic acid decarboxylase activity were found between strains at any age. The susceptibility of DBA/2 mice to audiogenic seizures does not result from a gross inability to synthesise or store GABA.