Bibliographic
Type 2 diabetes mellitus (T2DM) and Alzheimer's disease (AD) share specific molecular mechanisms, and agents with proven efficacy in one may be useful against the other. The glucagon-like peptide-1 (GLP-1) receptor agonist exendin-4 has similar properties to GLP-1 and is currently in clinical use for T2DM treatment. Thus, this study was designed to characterize the effects of exendin-4 on the impairment of learning andmemory induced by amyloid protein (Aβ) and its probable molecular underlying mechanisms. The results showed that (1) intracerebroventricular (i.c.v.) injection of Aβ1–42 resulted in a significant decline of spatial learning and memory of rats in water maze tests; (2) pretreatment with exendin-4 effectively and dose-dependently protected against the Aβ1–42-induced impairment of spatial learning and memory; (3) exendin-4 treatment significantly decreased the expression of Bax and cleaved caspase-3 and increased the expression of Bcl2 in Aβ1–42-induced Alzheimer's rats. The vision and swimming speed of the rats among all groups in the visible platformtests did not show any difference. These findings indicate that systemic pretreatmentwith exendin-4 can effectively prevent the behavioral impairment induced by neurotoxic Aβ1–42, and the underlying protectivemechanismof exendin-4may be involved in the Bcl2, Bax and caspase-3 pathways. Thus, the application of exendin-4 or the activation of its signaling pathways may be a promising strategy to ameliorate the degenerative processes observed in AD.