The alpha-7 nicotinic acetylcholine receptor agonist GTS-21 does not affect food intake in rats

Obesity is a prevalent disease, but effective treatments remain limited. Agonists of the alpha-7 nicotinic acetylcholine receptor (alpha 7nAChR) promote negative energy balance in mice, but these effects are not well-studied in rats. We tested the hypothesis that the alpha 7nAChR agonist GTS-21 would decrease food intake and body weight in adult male Sprague Hawley rats. Contrary to our hypothesis, acute systemic administration of GTS-21 produced no significant effects on chow or high-fat diet (HFD) intake. Acute intracerebroventricular (ICV) GTS-21 also had no impact on chow intake, and actually increased body weight at the highest dose tested. Previous studies suggest that GTS-21 engages the food intake-suppressive glucagon-like peptide-1 (GLP-1) system in mice. As there are known species differences in GLP-1 physiology between mice and rats, we tested the ability of GTS-21 to elicit GLP-1 secretion in rats. Our results showed that plasma levels of total GLP-1 in rats were not significantly altered by peripheral GTS-21 injection. These results represent an advance in understanding how alpha 7nAChR activation impacts energy balance control in rodents and suggest that there may be important differences between rats and mice in the ability of GTS-21/alpha 7nAChR activation to increase secretion of GLP-1.