Mechanisms of glucagon-like-peptide 1 in the brain beyond metabolic effects

Ever since its discovery, glucagon-like-peptide 1 (GLP-1) and drugs with similar function (collectively GLP-1s) have been used for type 2 diabetes mellitus and have been effective for obesity. Their profound effect on weight loss has resulted in widespread use of these medicines for treating obesity. Extensive studies have shown that GLP-1s decrease body weight, lean mass, and other metabolic phenotypes. These studies were supported by the mechanism of signaling pathways of GLP-1s in cells and their metabolic effects. Recently, studies have focused on the effect of GLP-1s on the brain, showing that they affect food cognition, depression, drug addiction, and even neurodegenerative diseases. Although recent studies have investigated the impact of GLP-1s on the brain, our understanding of these effects is limited. This review describes how GLP-1s have become the most effective drugs in obesity, such as their known signaling pathway in cells and their pharmaceutical processing over the years. This review covers recent discoveries of the GLP-1 mechanisms in the brain, including their prominent effects on obesity, and discusses discoveries that imply their potential usage in brain disorders.