Lack of effect of aspartame or of l-phenylalanine on photically induced myoclonus in the baboon, Papio papio

Abstract

The effects of large doses of l-phenylalanine and of aspartame on seizure susceptibility and severity have been assessed in baboons Papio papio from Senegal which show photosensitive epileptic responses similar to primary generalised epilepsy in man. l-Phenylalanine, 50, 150 or 450 mg/kg, or aspartame, 300 or 1000 mg/kg, were administered orally. Peak plasma l-phenylalanine concentrations of approximately 2000 μmoles/1 occurred 1–4 h after the highest dose of l-phenylalanine or aspartame. The plasma l-phenylalanine to large neutral amino acid ratio increased approximately 30-fold at this time. Compared with water administration there were no changes in epileptic responses 1–5 h after either treatment. In this primate model of epilepsy acute increases in plasma phenylalanine concentration are neither pro- nor anticonvulsant.