The effect of pre- and post-natal nitrate exposure on inhibitory avoidance memory in mice

Nitric oxide (NO) is directly involved in mechanisms responsible for fetal neurogenesis and development. It has also been shown that NO can impair or improve learning and memory in different models. There is evidence that administration of nitrate can produce NO. This study aimed at examining the effect of pre- and post-natal nitrate exposure on inhibitory avoidance memory in mice and measuring the NO metabolites herein. In this experimental study, 28 pregnant mice were divided into 4 groups: 1) Control group (whose mothers received only drinking water during the pregnancy and post-natal), 2) Treatment Group (whose mothers received sodium nitrate (100 mg / l) in drinking water during the pregnancy and post-natal until the 6th and 11th day after birth). During a two-day session (training and test) the learning and memory of animals (30 days after receiving sodium nitrate) were studied in a step down apparatus. The latency time for coming down from the platform in the test day (S) was used as a criterion for memory. The nitrate oxide metabolites in brain tissue were measured by Miranda method. The nitrite to nitrate recovery and total nitrite measurements were performed using Griess reagents with a spectrophotometer. The oral administration of sodium nitrate (100 mg/L) during pregnancy and lactation until 11 days after birth improved the avoidance memory compared to the control group (P<0.05). Also, sodium nitrate did not change the NO metabolites during those time periods. The oral sodium nitrate in pregnancy and lactation period improves mice avoidance memory without an alternation in nitric oxide metabolites.