The association between risky decision making and cocaine conditioned place preference is moderated by sex

Abstract

Background: Excessive risk taking is a characteristic trait of several psychiatric conditions, including substance use disorders. High risk-taking (HiR) rats self-administer more cocaine compared to low risk-taking (LoR) rats. However, research has not determined if risk taking is associated with enhanced cocaine conditioned place preference (CPP).

Methods: Male and female Sprague Dawley rats (n = 48 each sex) were first tested in the risky decision task (RDT), in which a response on one lever resulted in safe delivery of one food pellet, and a response on a different lever resulted in delivery of two pellets and probabilistic delivery of foot shock. Following RDT training, rats were tested for cocaine CPP. The first session was a pretest that measured rats' preference for three compartments that provided different visual and tactile cues. Rats then learned to associate one compartment with cocaine (either 10.0 mg/kg or 20.0 mg/kg; i.p.) and one compartment with saline (1.0 ml/kg; i.p.) across eight conditioning sessions. Finally, rats explored all three compartments in a drug-free state.

Results: Sex significantly moderated the association between risky decision making and cocaine CPP. While increased risk aversion was somewhat positively associated with cocaine CPP in males, increased risk taking was positively correlated with cocaine CPP in females.

Conclusions: These results highlight the moderating role of sex on the relationship between risky decision making and cocaine reward.

Keywords: Cocaine; Conditioned place preference; Conditioned rewarding effects; Individual differences; Rat; Risk taking; Risky decision task; Sex differences.