 The study aimed to investigate the precise location and physiological relevance of GLP1 receptors, GLP1R, in the mouse brain using the GLP1R CRE mouse as a functional tool. The researchers used patch clamp recordings and viral gene delivery to identify GLP1R expressing cells in various regions of the brain, including the circumventricular organs, amygdala, hypothalamic nuclei, ventrolateral medulla, nucleus of the solitary tract, thalamic paraventricular nucleus, hippocampus, and cortex. They found that GLP1R cells were not immunoreactive for GFAP or parvalbumin but were catecholaminergic. The study confirmed GLP1R expression in wholesale recordings from the brainstem, hippocampus, and thalamic paraventricular nucleus were 100 nm GLP1 elicited a reversible inward current or depolarization. The researchers also demonstrated the power of combining the GLP1R CRE mouse with a virus to generate a selective molecular handle for future in vivo investigation of GLP1R's physiological importance. This article was authored by Simon C. Cork, James E. Richards, Marie K. Holt, and others.