Determination of the extracellular basal levels of glutamate and GABA at dentate gyrus of streptozotocin-induced diabetic rats.

Previous studies have indicated an association between diabetes mellitus and impairments in synaptic plasticity in the hippocampus. However, it is not clear if the impairments of synapses are pre- or post-synaptic or both. The aim of this study was to evaluate the extracellular basal levels of glutamate and GABA at dentate gyrus of anesthetized streptozotocin-induced diabetic rats, after 12 weeks of diabetes induction. Extracellular levels of glutamate and GABA were investigated by using the microdialysis technique coupled to high performance liquid chromatography (HPLC) with fluorescent detection. Experimental groups were the control group and the diabetes group. The results showed that glutamate levels were significantly decreased in diabetes group compared to the control group, while GABA levels showed no changes. The findings support the possibility that alterations in transmission may account, in part, for synaptic plasticity deficits induced in diabetes.