Effects of hypoglycemia on the transmitter pool and the metabolic pool of glutamate in rat brain.

The glutamate terminals in rat neostriatum were removed by unilateral frontal decortication. Insulin-induced hypoglycemia was accompanied by different changes in amino acids in rostral neostriatum on the intact and lesion side. Thus the glutamate/aspartate ratio, glutamate concentration and glutamine concentration were significantly more reduced and the aspartate concentration more elevated on the non-operated than on the operated side. The results show a higher turnover of glutamate in the non-operated side indicating a higher turnover of the transmitter pool than of the metabolic pool of glutamate. The combination of brain lesions with drugs inhibiting the metabolism points to a new method to investigate the compartmentation of glutamate in the mammalian brain.