Abstract
Glutamate is one of the most abundant excitatory neurotransmitters of brain, plays an important role in learning and memory. Monosodium glutamate (MSG) is a sodium salt of L-glutamate, a well-known flavor enhancer. Because of its capacity to increase the palatability, nowadays it is most widely used in all households and fast foods. The present study investigates the effect of MSG on striato-hippocampal acetylcholinesterase (AChE) level in the brain of male wistar albino rats and its implications on learning and memory during aging. The experimental groups consisted of 3 - 4 weeks old Wistar albino rats and were divided into group I and group II. These groups were again subdivided into control group treated with laboratory diet, 100 mg MSG, 400 mg MSG, 2 g MSG and 4 g MSG group treated with various doses of MSG/kg body weight for sixty days. Immediately after 60 days of MSG treatment, the group I was used for the analysis of body weight, T-maze test, novel object recognition test (NOR) and AChE level while group II was kept free of MSG for further sixty days and later used for the above experiments. The results showed that group I animals neither have a dose dependent increase in body weight, a decline in the T-maze response, reduced discrimination index in NOR test and an increase in AChE level. However, the changes were significant at 4 g MSG treated group. The group II animals did not showed any significant differences when compared to control group. Thus the study revealed that a long term administration of MSG has a capacity to cause cognitive impairment but is not perpetual, during the life time, due to normal diet and natural healing mechanisms in the body ameliorates the toxic effects of MSG and showed gradual increase in the cognitive parameters, however it take a long time.