The current project intends to investigate the role of the gut peptide glucagon-like peptide-1 (GLP-1) in central taste processing and how GLP-1 may alter taste in an animal model of obesity. Specifically, the proposal will investigate how taste stimuli which are perceived as palatable are influenced by GLP-1 using a combination of behavioral, pharmacological, and electrophysiological methods.
Specific Aim 1 will determine GLP-1's involvement in gustatory reward behaviors in lean vs. dietary obese (DIO) male Sprague-Dawley rats. To do so, various doses of GLP-1 will be administered into the 4th ventricle prior to brief taste tests or longer-access preference and intake tests of palatable carbohydrates in lean and DIO rats.
In Specific Aim 2, neural taste and reward responses to GLP-1 in DIO rats will be characterized. Again, lean and DIO rats will be used to investigate changes in the firing patterns of taste neurons within the pontine parabrachial nucleus (PBN) and dopamine neurons within the ventral tegmental area (VTA) following GLP-1 administration. We expect that GLP-1 will reduce taste preferences and carbohydrate intake, and corresponding changes in neural firing patterns will be observed within the PBN and VTA. We also that GLP-1 will normalize firing rates of DIO rats, but will be slightly less effective, requiring higher doses to achieve the same effects as lean rats. These results will enhance the general knowledge of how central GLP-1 mediates feeding behaviors and provide further insight into the potential of GLP-1 as a treatment for obesity caused by excessive caloric consumption.
The current project studies the influence of the gut peptide GLP-1 in the processing of taste information, specifically in obesity. Understanding how GLP-1 changes the perception of taste could lead to greater understanding of the mechanisms driving consumption and food choices. Furthermore, GLP-1 could be used as a therapeutic target in obese individuals to help control meal size and cravings for sweet meals.