Chronic restraint stress facilitates the acquisition of cocaine self-administration.

AVALOS, M.P.; BOLLATI FLAVIA; GUZMAN A; CONSTANZA GARCÍA-KELLER; CANCELA, L.

Mar del Plata

Congreso; XXX SAN Annual Meeting; 2015

Sociedad Argentina de Investigación en Neurociencia.

Clinical evidence supports the idea of individuals that suffer stressing events along their lives are vulnerable to developing substance use disorders (SUDs). Here, we attempted to mimic how exposure to chronic stressful life events can create a vulnerability to developing SUDs. Sprague-Dawley rats were exposed to chronic restraint stress (2 hs daily) during seven days. A week after the last stress session, all animals were anesthetized and implanted with indwelling jugular catheters. Seven days after surgery, rats began daily 2 hs cocaine self-administration (SA) sessions (fixed ratio 1), in which one response on the active lever yielded one intravenous cocaine infusion (0.2 mg/infusion, followed by a 5 s time-out period), paired with a white cue light above the active lever and a discrete tone cue. An inactive lever was also available throughout each session. Rats were allowed ten days to reach SA criterion, which was defined as the first day animals obtaining more than ten infusions of cocaine. Our results point out a facilitation of the acquisition of cocaine SA as well an augmented intake of cocaine in pre-stressed animals as regard to control unstressed animals. This behavioral facilitation induced by chronic stress on cocaine SA was proved by quantifying the ratio of response on the active lever and the amount of cocaine infusions, these findings constitute a starting platform to study the mechanisms underpinning the comorbility between stress and SUDs.