Folic acid deficiency during the suckling period was induced by intraperitoneal injections of aminopterin to both lactating dams and offsprings in the following way; in the case of lactating rats, aminopterin 0.038mg/kg. 0.038mg/kg and 0.076mg/kg, was given on the 4th, 10th and 18th days of delivery, respectively, and in the case of offpsrings, aminopterin, 0.038mg/kg, was given only on the 18th day of life.
At the age of 6 weeks rats thus treated were examined for DNA and RNA content of the brain, lipids in myelin fraction, and analyzed for basic waves of EEG.
The results revealed that, in 6-week-old rats with the aminopterin-treatment during the suckling period, there was a significant decrease in both cholesterol and phospholipids contents of myelin fraction and a definite delay of the maturation pattern of the EEG basic waves.