GLP-1 agonism alters local field potential in the lateral septum and alters operant behavior in rats

Abstract

GLP-1 agonists are an emerging treatment for disorders of consumption. They are most prominent as treatments for obesity, but recent literature suggests that they are effective at reducing the consumption of all types of hedonic substances. This clearly suggests a central, cognitive, mechanism rather than a peripheral mechanism or an interaction with a single signalling pathway, but the specific site or sites for this mechanism remain to be discovered. Candidate brain regions for this reward-modulating activity have a relative paucity of GLP-1 receptors, with the exception of lateral septum, which expresses an abundance of them. In these experiments we recorded local field potential from lateral septum while animals received either saline control or the GLP-1R agonist liraglutide. We find that liraglutide significantly reduced the power of both high-frequency oscillations and theta rhythm in the lateral septum, suggesting that GLP-1R agonism changes how lateral septum communicates with its network. In addition, we show that liraglutide causes animals to wait longer to respond for reward in a differential reinforcement of low rates paradigm. Together, these results suggest that a primary region in the control of the anticonsumptive action of GLP-1 agonists is the lateral septum, and that the coding of reward by this region is a central node in the network responsible for cognition about and behaviour with respect to reward.