416— The effects of early life trauma on anxiety and alcohol use is modified by environment

Early life trauma is a risk factor for later anxiety and alcohol use disorders. However, the role of the post-trauma environment on the development of such disorders is not well understood. In the present study we investigated experience-dependent changes in anxiety and alcohol use after exposure to early trauma. Young mice (day 23) were exposed to a predator odor (synthetic fox pheromone, TMT) and then reared in either standard (SE) or enriched environments (EE). Adolescent anxiety and conditioned fear were reduced in EE-males, but not EE-females. Adult mice were then tested for their preference to drink alcohol. Alcohol intake escalated across sessions for all mice, however, EE mice had overall lower levels of alcohol use. Interestingly, exposure to TMT affected alcohol preference in EE mice, but not standard mice. Findings demonstrate the environment as a developmental modifier of post-trauma anxiety and alcohol use disorders

159— The effects of trauma on the response to cocaine

Exposure to adverse events is a risk factor for substance use disorder. We modeled this in an inbred strain of mice by exposing adult males to a predator odor (a synthetic fox pheromone, TMT) and then assessing 1. Cocaine-induced locomotion, and 2. Conditioned place preference (CPP) of cocaine. TMT was an effective stressor as indicated by freezing behavior, an absence of movement that is an instinctive fear response in mice. Interestingly, in a 1-hour baseline locomotor test, TMT-exposed (TMT+) mice were more active than non-exposed (TMT-) mice. In addition, following a cocaine (10 mg/kg) injection (i.p.) TMT+ mice showed a cocaine-induced increase in activity, whereas TMT- mice did not. Finally, mice were conditioned to associate one side of a 3-chambered arena with cocaine (10 mg/kg) and were then tested in a 30-minute session of free exploration (15 minutes of cue-prime, 15 minutes of drug-prime). One week later, an identical 30 min session of free exploration was conducted. The time spent inside the drug-associated context was considered an indication of the rewarding properties of cocaine