Long-term exposure to high glucose induces changes in the expression of AMPA receptor subunits and glutamate transmission in primary cultured cortical neurons.

Hyperglycemia, which occurs under the diabetic conditions, induces serious diabetic complications. Diabetic encephalopathy has been defined as one of the major complications of diabetes, and is characterized by neurochemical and neurodegenerative changes. However, little is known about the effect of long-term exposure to high glucose on neuronal cells.

Exendin (5-39), an antagonist of GLP-1 receptor, modulates synaptic transmission via glutamate uptake in the dentate gyrus.

Extracellular concentrations of glutamate are mainly controlled by an astrocytic glutamate transporter, GLT-1. We previously reported that exendin (5-39) (Ex), an antagonist of the GLP-1 receptor, improved memory impairment in β-amyloid protein-treated rats. In this study, we investigated effects of Ex on synaptic transmission through astrocytic GLT-1 in the hippocampus.