[Effects of maternal exposure to a single dose of kainic acid on the functional development of the brain in the rat].

Effects of maternal exposure to a single and small dose of kainic acid (KA) on the functional development of the offspring were studied in the rat. A single dose of KA at 3 mg/kg or distilled water (DW) was injected on one day during days 11-14 (G11KA-G14KA, G11DW-G14DW) or 17-19 (G17KA-G19KA, G17DW-G19DW) of gestation. The body growth of G14KA-G18KA was significantly larger than that of the controls. In an open-field, alterations observed in the KA-exposed rats were 1) a reduction of the latent time to the first line crossing at 15 days of age, 2) a decrease in ambulation score at 17 days of age and 3) early appearance of rearing behavior at 15 days of age. Frequencies of spontaneous head shakes, grooming and urination during the open-field test were in the normal range. The frequency of 9 mg/kg KA-induced wet-dog shakes increased only in the G17KA male rats when tested in the 5-week-old G12KA, G14KA and G17KA groups. The results indicated that prenatal exposure to a single dose of KA affects the body growth and behavior development during the infantile period in rats. The alterations in the growth and behavior appear to correlate with the exposure time to KA, days 13-18 of fetal life, which is the principal time of neurogenesis in the hippocampus, cerebral cortex and hypothalamus.