[Epileptic seizure model utilizing additive effects of excitatory amino acids]

L-glutamate (GLU) and L-aspartate (ASP), major excitatory amino acids in the brain, are believed to have an important role in the generalization and expression of epileptic seizures. Their analogues such as kainate, folate, ibotenate and quisqualate have been widely used to produce epileptic seizures, since they have a potent excitatory action. However, these analogues produce striking neuronal damage at the injection site when injected intracerebrally. Therefore, these analogues are not appropriate for studying the mechanisms of epilepsy, which is believed to be based on the functional changes of the brain. On the other hand, although GLU and ASP themselves have minimal neurotoxic action, a relatively higher dosage than that of their analogues is needed to produce epileptic seizures. A recent report, in which Freeman has found that combined GLU/ASP released from the lobster neuromuscular synapse in a molar ratio of 1:3 (GLU/ASP) produces strong excitation, may provide some clue to this problem. In this study, we examined the features of epileptic seizures and neuronal damage following the injection of GLU/ASP combined in this molar ratio into the amygdala (AM) of rats. Twenty-nine adult male Wistar rats weighing 200-250 g were used. All animals had received a cannula made of a 22-G stainless steel tube into the left AM. A bipolar recording electrode made of stainless steel wire was attached to its wall.(ABSTRACT TRUNCATED AT 250 WORDS)