Effect of prenatal undernutrition and phenobarbitone administration on discrimination learning and passive avoidance behaviour in rats.

Effects of prenatal undernutrition and phenobarbitone administration, individually and conjointly, was assessed on learning acquisition and subsequent retention of a black/white discrimination task and passive avoidance behaviour in rats. Undernutrition of the dams was induced by restricting food intake to half, throughout the period of gestation, whereas phenobarbitone sodium (2.5 mg/kg, ip) treatment was given from day 13 to 20 of gestation, this being the critical period for neural development in rats. The pups were subjected to brightness discrimination learning, retention of the learning acquisition in a single unit black/white T-maze and passive avoidance behaviour test at 8-9 weeks of age. The results indicate that prenatal undernutrition induces significant discrimination learning and retention deficits in the offsprings. Prenatal phenobarbitone treatment also caused significant learning acquisition and retention deficits in the discrimination test. Phenobarbitone augmented the learning and retention deficits induced by undernutrition. However, both prenatal undernutrition and phenobarbitone treatments did not affect the retention of the learned passive avoidance. The results indicate that the prenatal interference in the form of undernourishment and anticonvulsant barbiturates, may induce functional deficits resulting in perturbed cognition in the offsprings.

Effect of gestational undernutrition and chlordiazepoxide treatment on black/white discrimination learning and retention in young rats.

Effects of prenatal undernutrition and chlordiazepoxide treatment on learning acquisition, and subsequent retention, of a black/white discrimination task, was assessed in the offspring. Undernutrition of the dams was induced by restricting food intake to half, throughout the period of gestation, whereas chlordiazepoxide (2.5 mg/kg, ip) treatment was given from day 13 to 20 of gestation, this being the critical period for neural development in this species. The pups born were subjected to brightness discrimination learning, and retention of the learning acquisition after an interval of one week, in a single unit black/white T-maze, at 8-9 weeks of age. The results indicate that prenatal undernutrition induces significant learning and retention deficits in the offspring. Prenatally administered chlordiazepoxide induced significant deficits in learning acquisition and subsequent retention of the discrimination problem. Chlordiazepoxide induced similar learning and retention deficits in the normal and undernourished rats, and exaggerated the learning and retention deficits induced by undernutrition. The results indicated that the prenatal insults in the form of undernourishment and anxiolytic benzodiazepine compounds, leave a lasting imprint on cognitive behaviour of the offspring.

Effects of gestational undernutrition, stress and diazepam treatment on spatial discrimination learning and retention in young rats.

Effects of prenatal undernutrition, stress and diazepam treatment on learning acquisition, and subsequent retention of a spatial discrimination task was assessed in the offsprings. Undernutrition of the dams was induced by restricting food intake to half, throughout the period of gestation, whereas footshock stress and diazepam (0.5 mg/kg, ip) treatment was given from day 13 to 20 of gestation, this being the critical period for neural development in this species. The pups born were subjected to spatial discrimination learning, and retention of the learning acquisition after an interval of one week, in a single unit black/white T-maze, at 8-9 weeks of age. The results indicate that prenatal undernutrition induces significant learning and retention deficits in the offspring, whereas the effect of prenatal stress was limited to only deficit in learning acquisition. Prenatally administered diazepam induced significant deficits in learning acquisition and subsequent retention of the discrimination task in pups culled from normally nourished dams. However, offsprings from diazepam administered undernourished dams exhibited less marked cognitive deficits, which may be attributable to the altered emotional reactivity of pups born to undernourished mothers. Prenatally administered diazepam also induced differential effects in stressed and non-stressed dam offsprings, though the effects were statistically insignificant. The results suggest that prenatal insults, in the form of undernourishment, stress and anxiolytic drugs, leave a lasting imprint on cognitive behaviour of the offspring. The final effect on this behaviour may be determined by the co-existence of these prenatal factors, particularly at a time when the foetus is vulnerable because of neural development and differentiation.

EEG spectral power reduction and learning disability in rats exposed to lead through postnatal developing age.

The present study was carried out to assess electrophysiological and behavioral changes in Wistar rats caused by consuming a daily dose of lead acetate (400 micrograms lead/g body weight/day, given by gastric intubation, from second day of birth to 60 days of age. At 60 days of age, the lead treated rats showed in both wakeful and slow wave sleep stages, a statistically significant reduction in the delta, theta, alpha and beta band EEG spectral power in motor cortex (MC) and hippocampus (HI) with the exception of the delta and beta bands power of MC in wakeful state (WA). Lead administration was discontinued after that age for allowing rehabilitation for 40 days. Then, operant behavioral assessment was done. Results revealed that the lead treated animals took significantly more time and sessions than control normal animals in attaining criterion of learning. Hence exposure to lead in early age could result in a learning disability persisting even after discontinuation of exposure.

Effect of piracetam, a nootropic agent, on discrimination learning deficits induced by parental undernutrition and environmental impoverishment in young rats.

The study was conducted on 64 Charles Foster albino rats which were equally distributed into 8 even-matched groups, following a 2 x 2 x 2 factorial design by varying three independent factors at two levels: nutrition--normal and undernutrition, environmental--enrichment and impoverishment, and drug treatment--vehicle and piracetam (100 mg/kg, ip). Prenatal nutrition was induced by restricting the mother's food intake. The environmental enrichment/impoverishment and the vehicle/drug treatments were given during the postweaning period of the rat pups. The animals were subjected to original and subsequent reversal brightness discrimination learning tests in a single unit T-maze at 8-9 weeks of age. The results indicate that undernutrition and environmental impoverishment significantly attenuated the original discrimination as well as the reversal discrimination learning. Piracetam treatment improved the learning performance of normally reared rats and also attenuated the original and reversal learning deficits induced by prenatal undernutrition and postnatal impoverishment. The results indicate that piracetam may be useful in memory deficits induced by malnutrition.