Absence of an effect of aspartame on seizures induced by electroshock in epileptic and non-epileptic rats.

Seizure facilitation has been proposed as a possible adverse effect of dietary consumption of aspartame. The conversion of this sweetener to phenylalanine and aspartate in the gastrointestinal tract, and subsequent absorption, elevates plasma levels of these two amino acids. Absorbed phenylalanine competes with other large neutral amino acids, including tyrosine and tryptophan, for transport into brain. Theoretically, this competition might reduce brain tyrosine and tryptophan which could decrease synthesis of norepinephrine, dopamine and serotonin. Diminished synaptic release of these monoaminergic neurotransmitters facilitates seizures in many seizure models. Our present study evaluates effects of oral aspartame on amino acids and electroshock seizures in normal and seizure predisposed rats. Heroic doses of aspartame produced predićtable changes in plasma amino acids. However, none of the aspartame doses altered seizure indices. We conclude that aspartame does not alter maximal electroshock seizures in normal rats or in rats predisposed to seizures.