Female rats eating high fat chow acquire methamphetamine self‐administration faster than rats eating standard chow

Abstract

Eating a diet that is high in fat contributes to increased risk of chronic diseases and mortality, even in the absence of obesity. Eating a high fat diet can also impact the same brain reward pathways that are targeted by drugs of abuse. Preclinical studies have demonstrated that rats eating high fat chow are more sensitive to the unconditioned behavioral effects of drugs that act on dopamine systems (e.g., cocaine). However, the majority of evidence demonstrating that diet can impact drug sensitivity has investigated only male subjects, despite probable sex differences. To test the hypothesis that eating high fat chow increases sensitivity of rats to the positive reinforcing effects of methamphetamine (0.01–1.78 mg/kg/infusion), female Sprague‐Dawley rats (n = 30) were fed either standard (17% kcal from fat) or high fat chow (60% kcal from fat) for 6 weeks prior to self‐administration procedures. Following i.v. catheter implantation, rats were trained to respond for 0.1 mg/kg/infusion methamphetamine under a Fixed Ratio 1 schedule of reinforcement. Rats eating high fat chow met acquisition criteria faster (14 +/−2 days) than rats eating standard chow (25 +/− 4 days). Preliminary (n = 5–8/group) dose‐response curve assessments under a Fixed Ratio 5 schedule of reinforcement revealed that rats eating high fat chow respond less for methamphetamine than rats eating standard chow, at least at the training dose (0.1 mg/kg/infusion). These results suggest that rats eating high fat chow are more sensitive to the reinforcing effects of methamphetamine than rats eating standard chow. Future work will examine the relative reinforcing effectiveness of methamphetamine in rats eating different diets using a progressive ratio schedule of reinforcement. These data expand previous research and add to the growing literature on the effects of diet on drug sensitivity.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.