Caffeine is the most consumed psychoactive drug in the world yet animal research has been unable to establish caffeine as a reinforcer. However, caffeine functions as a reinforcement enhancer, potentiating motivation to obtain reinforcers. The combination of alcohol with caffeine has become an issue of public health concerns within the past decade. The goal of this study was to understand the reinforcement enhancing effects of caffeine on alcohol intake. Additionally, the potentiating effects of saccharin on alcohol consumption were observed. Eighteen male mice were trained to lever-press for one of 3 different solutions: ethanol alone (5%), ethanol (5%)+caffeine, and ethanol(5%)+saccharin(0.2%). Caffeine concentrations (0, 1.25, 2.5, 5, and 7.5 mg/ml) were changed every five days to examine a dose-response relationship. Mice responded on a Progressive Ratio (PR) schedule of reinforcement during a 1-hr session. Active lever presses, inactive lever presses, and reinforcers earned were calculated after each session.
Nice work, all. Thanks for posting it.
Thank you very much!