Dose respond effect on spatial memory and somatosensory after acute and chronic of monosodium glutamate exposure in adults rats / Muhammad Zulhafiz Zulkupli

In order to explore the dose respond effect on spatial memory and somatosensory after acute and chronic exposure of Monosodium Glutamate (MSG), adult rats were administered intraperitoneally with MSG for 21 days with dose 2.0 mg/g, 4.0 mg/g and 8.0 mg/g per body weight. Normal saline was administered intraperitoneally as control. In this study, the methodology for the validation of MSG effects on central nervous system and cognitive function has been applied. Spatial memory impairment was assessed with the use of Morris Water Maze (MWM) task. On the other hand, the somatosensory impairment was evaluated using the sticky-tape test whereby, animals were assessed according to their ability to remove the stimulus (sticky-tape). On day 1, 7, 14 and 21, Morris Water Maze and sticky-tape test were conducted in this study. No significant different in behavioral performance between the control and MSG treated rats were found in all paradigms which have been measured. In rats, such MSG treatment with doses of 2.0 mg/g and 4.0 mg/g do not cause statistically significant on spatial learning deficits in MWM task and also do not reveal any somatosensory dysfunction. Moreover it does not attribute to a subsequent increasing in body weight as reported in previous study. Additionally administration of very high concentration of MSG (8.0mg/g) caused hyperactivity of the glutamate system and induce convulsion after the treatment. These observations support that the ability of large, concentrated doses of MSG to produce brain lesions. Nevertheless this study does not really support and extends earlier study that MSG treatment produces behavioral changes.