Threat Conditioning Prior to Cocaine or Sucrose Exposure Alters Reward-Seeking Behavior in a Sex-Dependent Manner

Research has shown a high prevalence of co-occurring trauma-related disorders and cocaine use disorder (CUD). However, there remains a need for preclinical studies to determine how traumatic event exposure influences vulnerability to CUD development and relapse. In this study, we assessed the impact of traumatic event exposure using a threat conditioning (TC) paradigm, which models traumatic event exposure through associative threat learning on cocaine-seeking behavior in adult male and female rats.

Adult male and female rats were exposed to a single TC session. After TC, the rats underwent cocaine self-administration (SA), extinction training, cue-primed reinstatement, and cocaine-primed reinstatement testing. A parallel cohort was subjected to a sucrose SA cohort to assess whether TC altered non-drug reward seeking in the form of sucrose SA.

In the cocaine cohort, stressed male rats exhibited greater cue- and cocaine-primed reinstatement relative to non-stressed males, whereas no reinstatement differences emerged in female rats. In the sucrose cohort, stressed females displayed increased sucrose pellet delivery during self-administration compared to non-stressed females, but no differences were observed during sucrose reinstatement in either male or female rats.

These findings indicate that trauma exposure prior to cocaine use influences cocaine relapse-related behavior, as well as non-drug reward reinforcement earning, in a sex-specific manner. Overall, these results highlight the value of associative stress models such as TC for studying trauma-addiction comorbidity and the need to investigate the neurobiological mechanisms driving these sex-specific outcomes.