Non-contingent electric footshock facilitates the acquisition of intravenous cocaine self-administration in rats

摘要: The experiments described below were designed to investigate whether contingent versus non-contingent electric footshock would affect the acquisition of intravenous cocaine self-administration in rats. During first component a multiple schedule, triads rats trained respond under discrete-trial, fixed-ratio 10 schedule food reinforcement. Random presentation (0.6 mA) for and second from each triad was yoked lever responding by group only, while third never shocked. When stable baselines food-reinforced obtained, all three allowed self-administer increasing doses (0.031–0.5 mg/kg per infusion) during component. Rats group, receiving noncontingent presentation, self-administered (0.125 at higher rates one-half dose which maintained other two treatment groups. Plasma corticosterone, measured before self-administration, highly correlated with drug intake this concentration groups These data demonstrate that experimental stress facilitates