Epilepsy Res. 1989 Jul-Aug;4(1):1-7.

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

Meldrum BS, Nanji N, Cornell RG.

Department of Neurology, Institute of Psychiatry, De Crespigny Park, Denmark Hill, London, U.K.

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 mumoles/l 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.