Effects of multivitamin B containing vitamins B6, vitamin B12 and folic acid on age- associated changes of rat brain glutamate metabolism

Glutamate (Glu) acts as an excitatory neurotransmitter in brain. Excessive levels of Glu in the brain are cytotoxic and lead to several neurodegenerative processes. Rapid removal of the released Glu in synaptic cliff may prevent the excessive excitation of Glu receptors. Several enzymes such as glutamine synthetase (GS) glutamate decarboxylase (GAD) and aminotransferases (GOT and GPT) are important for maintaining Glu concentrations below excitatory levels in the synaptic cleft. Since multivitamin B supplementation has been recommended as adjunctive treatment in Alzheimer's disease, this study was undertaken to investigate, .the efficacy of vitamins B6 and vitamin B12 and folic acid on the activities of GS, GAD, GOT and GPT in aging rat brain. Male Wistar rats (3 and 30 months old) were used. The animals were injected with vitamins B6 and vitamin B12 and folic acid (10mg/Kg/day) for 30 days and the day after the last injection the animals were killed by decapitated. Forebrains were homogenized in phosphate buffer and the activities of the enzymes were measured in the supernatant. The enzyme activities in aged rat brain were considerably lower compared to young animals. Vitamin B6 induced activation of GAD, GOT and GPT in both ages, but, the differences were more pronounced in aged animals. Vitamin B12 and folic acid stimulate the activity of GS in both young and old animals, but had lintel effects on GAD, GOT and GPT of both ages. It is concluded that Glu metabolism might be considered as a therapeutic target for prevention of neurodegenerative disorders and age related symptoms. Keywords— Aging, Alzheimer's disease, Glutamate, Multivitamin B, Neurotransmitter