GLP1R and obesity due to melanocortin 4 receptor deficiency: Since high-fat diet feeding attenuates CCK-induced activation of vagal afferents as well as responses in downstream brain regions (Covasa et al., 2000; Troy et al., 2016), alterations in GLP1R vagal afferent control of meal-related glycemia may also provide a neural mechanism underlying impaired glycemic control in obesity (Steinert et al., 2017).