The modifying influence of aging on behavior in mice neonatally injected with monosodium glutamate.

Newborn mice were injected with monosodium glutamate (MSG), and behavioral testing and physical development in neonatal, juvenile, adult, and aged mice were observed by means of a battery of appropriate tests. Early exposure to MSG resulted in altered behavioral performances postnatally, which were transitory and reflected the neurotoxicity of the chemical. Although behavioral deficits were not observed in mice neonatally treated with MSG at 1 month of age, a definite decline was manifested at 12 months and 34 months of age.