1973 Volume 13 Issue 4 Pages 235-244
Brain lesions induced by monosodium L-aspartate (MSA) in infant mice and fetuses were studied. A single subcutaneous dose of 6 mmole/kg of MSA was given to infant mice on the day of birth or on 5-day after birth, while pregnant females were treated subcutaneously with 30 mmole/kg of MSA on day 16, 17 or 18 of pregnancy. The brains of infant mice and fetuses were examined microscopically at several post treatment intervals. Brain lesions characterized by pyknosis and edematous change were found in the median portion of the olfactory bulb, preoptic area, hippocampus, habenular nucleus and hypothalamus. The extent of lesions in the hypothalamus varied with the developmental stages of infant mice and fetuses treated with MSA. With infant mice treated 5 days after birth, the lesions were localized in the arcuate nucleus of the hypothalamus. They were seen both in the arcuate and ventromedial nucleus in infant mice treated on the day of birth and in fetuses treated on day 17 or 18 of gestation. In fetuses treated on day 16, the lesions were localized in the ventromedial nucleus. The lesions disappeared within 48 hours of treatment in the infant mice, and disappeared within 24 hours of treatment in fetuses.