Effects of maternal deprivation on melatonin production and cognition in adolescent male and female rats

It is known that maternal deprivation (MD) may alter cognitive functions such as learning and memory in adult life by effecting normal growth and development. However, the mechanisms of these cognitive alterations are unknown. The aim of this study is to investigate the effects of maternal deprivation on cognition and melatonin production in adolescent male and female rats. The litters were separated daily from their mothers for 6 hours on postnatal days 2 to 20. The spatial memory performance was evaluated using a Morris water maze between the postnatal 26th and 32nd days. Plasma melatonin levels were determined on postnatal days 42. MD-rats had longer escape latencies at the second, third and fifth days of training days and spend significantly less time in probe trial, compared to control animals. The repeated maternal deprivation caused low blood melatonin levels and there was a significant negative correlation between blood melatonin levels and spatial memory performance in both of male and female adolescent rats. These results suggest an association between melatonin production and neurodevelopment. Further studies are needed to determine the interaction between maternal deprivation and pineal gland maturation/function.