Exendin (5-39) is a potent antagonist of the glucagon-like peptide 1 (GLP-1) receptor that can ameliorate memory impairment in rats treated with β-amyloid protein.

Intracerebroventricular administration of Exendin (5-39) at a dosage of 0.3 μg once daily for a week in male Wistar rats significantly augmented GLT-1 protein levels in the hippocampus. Additionally, hippocampal slices from Exendin (5-39)-treated or vehicle-treated rats demonstrated a decrease in fEPSP decay time, an enhancement in the input-output relationship, and a reduction in the paired-pulse ratio within the dentate gyrus (DG). Moreover, Exendin (5-39) was observed to inhibit long-term depression, albeit without affecting long-term potentiation in the DG. This effect was examined using an animal model comprising Wistar rats aged three weeks and those 18 days into pregnancy, underscoring Exendin (5-39)'s impact on hippocampal synaptic functions.