Exenatide enhances cognitive performance and upregulates neurotrophic factor gene expression levels in diabetic mice

Exenatide is a potent and selective agonist for the GLP‐1 (glucagon‐like peptide‐1) receptor. Recent studies are focused on the effects of GLP‐1 analogues on hippocampal neurogenesis, cognition, learning and memory functions. The aim of this study was to assess the effects of chronic exenatide treatment (0.1 μg/kg, s.c, twice daily for 2 weeks) on spatial memory functions by using the modified elevated plus maze (mEPM) test and emotional memory functions by using the passive avoidance (PA) test in streptozotocin/nicotinamide (STZ‐NA)‐induced diabetic mice. As the genes involved in neurite remodelling are among the primary targets of regulation, the effects of diabetes and chronic administration of exenatide on brain‐derived neurotrophic factor (BDNF) and cyclic adenosine monophosphate (cAMP) response element binding protein (CREB) messenger ribonucleic acid (mRNA) levels in the hippocampus of mice were also determined using quantitative real‐time polymerase chain reaction (RT‐PCR). This study revealed that in the mEPM and PA tests, type‐2 diabetes‐induced mice exhibited significant impairment of learning and memory which were ameliorated by GLP‐1 receptor agonist exenatide. Quantitative RT‐PCR revealed that CREB and BDNF gene expression levels were downregulated in diabetic mice, and these alterations were increased by exenatide treatment. Since, exenatide improves cognitive ability in STZ/NA‐induced diabetic mice and activates molecular mechanisms of memory storage in response to a learning experience, it may be a candidate for alleviation of mood and cognitive disorder.