Epileptic phenomena produced by kainic acid in laboratory rats during ontogenesis

Because of its preferential neuroexcitatory effects on the hippocampal neurones kainic acid (KA) is used for inducing partial seizures with a complex symptomatology. In this study the authors investigated the effect of intraperitoneal administration of KA, in doses of 2-16 mg/kg, on the laboratory rat during ontogenesis. The experimental animals were males aged 7, 12, 18, 25 and 90 days. The first signs of an effect in adult rats were automatisms; in young animals, jerks also appeared. The most important automatisms were wet dog shakes, which preponderated in 25-day-old and older animals, whereas in the young rats they consisted chiefly of intensive scratching. Minimal seizures with a motor pattern identical to minimal metrazol seizures were observed in all the age groups and so were generalized tonic-clonic convulsions, which appeared after large doses of KA. The systemic administration of KA is a convenient model of temporal seizures and their progressive generalization and could act as a model for testing broad spectrum antiepileptics.