Changes in Spontaneous Working-memory, Memory-recall and Approach-avoidance following “Low Dose” Monosodium Glutamate in Mice

The study investigated the effects of ‘low doses’ of monosodium glutamate (MSG) on hippocampal-related (spontaneous working-memory, memory-recall and anxiety) behaviours, and hippocampal glutamate/glutamine levels. A two-trial Y-maze test and 8-arm radial-arm maze spontaneous working-memory test were used to assess the effects of acute and repeated administration of MSG, on novel-arm choice on retrial and spatial working-memory; while anxiety-related behaviors were assessed in the elevated plus maze. In the elevated plus maze, radial-arm maze and Y-maze, MSG administration was associated with significant anxiolytic and memory-enhancing effects at 10 mg/kg (after both acute and repeated dosing); however, higher doses used in this study were associated with significant anxiogenesis and memory retardation. Hippocampal glutamate and glutamine levels did not increase significantly at any of the doses of MSG. In conclusion, MSG administration at low doses was associated with significant changes in hippocampal-dependent behaviours without a concomitant significant shift in hippocampal glutamate/glutamine levels.