Excitotoxic food additives: functional teratological aspects

Abstract

This chapter reviews the information pertaining to the potential teratological consequences of excitotoxin exposure in early life. The chapter uses the term “teratological” in its broad sense to include adverse effects on the organism at any preadult stage of development. The putative excitatory neurotransmitters, glutamate (Glu) and aspartate (Asp), and several of their structural analogues, comprise a family of excitotoxic compounds, which are so called because of their potential for destroying central neurons by excessive stimulation of postsynaptic excitatory membrane receptors. Despite evidence from animal studies that the immature nervous system is much more vulnerable than the adult to excitotoxin-induced damage, Glu and other excitotoxins are used quite heavily worldwide as additives to foods ingested by infants and children. In molecular specificity studies, it was found that specific structural analogues of Glu known to share the neuroexcitatory properties of Glu reproduce its neurotoxic effects, that these analogues have a parallel order of potencies for their excitatory and toxic actions and that analogues lacking excitatory activity also lack neurotoxicity.