Search

The present study reports various developmental and behavioral changes in the offspring of rat dams that received monosodium glutamate (MSG) in the drinking water all through the second and third trimesters of pregnancy. Three main effects were observed in the MSG exposed offspring: (1) juvenile obesity; (2) reduced general activity levels; (3) a specific type of learning disability in discrimination learning involving choice between simultaneously present positive and negative stimuli.

The effects of prenatal exposure to caffeine were studied on later physical development, behavior and brain neurochemistry. Daily doses (150, 300 or 450 mg/L) of caffeine were given to rat dams during the last week of pregnancy. Prenatal caffeine exposure resulted in a number of behavioral and neurochemical changes in the offspring which were long lasting and dose related. The low dose (150 mg/L) of prenatal caffeine caused hyperactivity in an open-field. The high dose of caffeine caused learning disabilities in complex visual and auditory discrimination learning paradigms while simple motor learning or a spatial orientation task were not affected. Both male and female offspring showed some behavioral effects of caffeine exposure. The medium and high doses of caffeine resulted in weight gain that was observable as early as 35 days of age and increased progressively with age. This weight gain was associated with increased food intake. The neurochemical studies carried out at 2-3 months of age revealed an increase in choline uptake in hippocampus, mainly in the animals treated with the lower doses of caffeine and higher protein concentration (microgram/mg wet tissue) in the cortex or hippocampus of offspring exposed to the higher doses of caffeine. At 15 months of age, choline uptake in the frontal cortex was significantly reduced in the animals prenatally exposed to the 300 and 450 mg/L dose.

Male mice isolated for either short or long time periods were paired in 10 min standard opponent tests with group-housed opponents with either 10 previous defeat experiences or no previous defeats. The results show that defeat experience increases the animal's readiness to assume and maintain submissive postures and that these postures in turn affect both the number of attacks and tail-rattles of the aggressor.Submission, once learned, was shown to be a more or less permanent change in behavior, resistant to the aggression-producing effects of isolation.

The purpose of this work was to study the effects of early embryonic treatment with estradiol on the aggressive behavior of cockerels, following castration and administration of testosterone or estradiol in adult life. Embryonal estradiol eliminated adult aggressive behavior. However estradiol activation after castration resulted in typical male cock fighting.

Zimelidine (5 mg/kg/day s.c.) was administered to pregnant rats from day 10 to day 20 of gestation. The development and later open field and learning capacities of their offspring were compared to those of saline injected and untreated dams. The development and behavior of prenatally zimelidine exposed offspring resembled those of the untreated rather than the saline injected group. Pups that were nursed by zimelidine treated mothers, however, showed behavioral deficits compared to those that were nursed by saline injected dams. Prenatal or early postnatal exposure to the 5HT uptake inhibitor zimelidine did not affect 5HT uptake and release measured at 3 months of age. Histological examination of major organs of prenatally zimelidine exposed animals showed no pathological changes.