Effect of monosodium glutamate (MSG) on behavior, body and brain weights of exposed rats

Purpose: Consumption of monosodium glutamate (MSG) in food, drink, and other consumables has been linked to different observable changes believed to be as a result of MSG's effects on the brain. Furthermore, it is believed that blood–brain barrier plays a role on how these effects are felt in different stages of life. The present study is an attempt to understand the differential effect of MSG by studying body and brain weights as well as physiological changes in the behavior of rats exposed at different stages of life (either as neonate or as adult). Materials and Methods: Pups were administered 4 mg/g MSG on postnatal days 2, 4, 6, 8, and 10, allowed to mature for 26 weeks, and afterward divided into three groups (n = 6) and administered saline, 5 mg/g, and 10 mg/g MSG for 6 weeks. Two other groups, not exposed to MSG at neonatal age (adult), were similarly administered 5 mg/g and 10 mg/g MSG for 6 weeks. During this period, weight gain and behavioral observation was made, and at the end of the 6 weeks, brain weight was measured. Results: A dose-dependent effect of MSG was recorded in both neonatal- and adult-administered rats in all the parameters studied. Conclusion: MSG affects both neonate and adult rats similarly, thus adult exposure may be used in studies involving MSG and other neurotoxic chemicals.