Tirzepatide Significantly Reduces Cocaine Motivation in Rodent Models

The GLP-1 (Glucagon-Like Peptide-1) and GIP (Glucose-dependent Insulinotropic Polypeptide) receptor agonists, like tirzepatide, are primarily known for their efficacy in treating type 2 diabetes and obesity by regulating glucose metabolism and appetite. Emerging research suggests these gut hormones also play a role in brain reward pathways, potentially influencing addictive behaviors. This study specifically aimed to investigate if tirzepatide, a dual GLP-1/GIP receptor agonist, could reduce the motivation for cocaine in preclinical models.

The study revealed a dose-dependent reduction in cocaine self-administration with tirzepatide treatment. At the highest dose of 1.0 mg/kg, tirzepatide significantly reduced the total number of cocaine infusions by 48% compared to the control group (p<0.001). Motivation for cocaine, measured by the progressive ratio breakpoint, was also markedly decreased; the 1.0 mg/kg tirzepatide group showed a 3.5-fold reduction in breakpoints (p<0.001) compared to controls. The most impactful finding was that tirzepatide at 1.0 mg/kg led to a 62% decrease in the number of rats meeting criteria for high cocaine-seeking behavior, indicating a profound anti-addictive effect. Importantly, tirzepatide did not significantly alter general locomotor activity or food intake at these doses, suggesting its effects were specific to reward pathways rather than general sedation or sickness. Furthermore, preliminary neurochemical analysis indicated a 30% reduction in cocaine-induced dopamine release in the nucleus accumbens of treated rats.