Yunjing Bai1,2, Yue Zhang3,4, Shaofei Jiang3,4, Xigeng Zheng3,4, Zhengkui Liu5,6. 1. CAS Key Laboratory of Mental Health, Institute of Psychology, 16 Lincui Road, Chaoyang District, 100101, Beijing, China. baiyj@psych.ac.cn. 2. Department of Psychology, University of Chinese Academy of Sciences, 19A Yuquan Rd, Shijingshan District, Beijing, 100049, China. baiyj@psych.ac.cn. 3. CAS Key Laboratory of Mental Health, Institute of Psychology, 16 Lincui Road, Chaoyang District, 100101, Beijing, China. 4. Department of Psychology, University of Chinese Academy of Sciences, 19A Yuquan Rd, Shijingshan District, Beijing, 100049, China. 5. CAS Key Laboratory of Mental Health, Institute of Psychology, 16 Lincui Road, Chaoyang District, 100101, Beijing, China. liuzk@psych.ac.cn. 6. Department of Psychology, University of Chinese Academy of Sciences, 19A Yuquan Rd, Shijingshan District, Beijing, 100049, China. liuzk@psych.ac.cn.
Abstract
BACKGROUND: Negative affective states, e.g., anhedonia, may be linked to the long-lasting motivational processes associated with relapse. Here, this study investigated whether, and how, anhedonic states are influenced by stressful events that contribute to craving and relapse. METHODS: All male rats were pretreated with a binge-like morphine paradigm for five days. After 12 to 16 days of withdrawal, rats were subjected to a one-hour free consumption test or three operant tasks with increasing cost/benefit ratio, i.e., fixed ratio 1 (FR1), progressive ratio (PR), and PR-punishment procedure of reinforcement, with sucrose solutions of three concentrations (4%, 15%, and 60%) as rewards. The consumption and operant responses under FR1 and PR procedures were measured following exposure to acute foot-shock stress (intermittent foot shock, 0.5 mA × 0.5 s × 10 min; mean intershock interval, 40 s), and the operant responses for 60% sucrose solution under PR-punishment procedure was measured following a forced-swim stress (5 minutes). RESULT: Foot-shock stress increased water consumption in a subpopulation of rats and decreased consumption of sucrose solutions, while it did not influence the operant responses for sucrose solutions under either FR1 or PR procedure. The forced-swim stress reduced operant responses for 60% sucrose solution under PR-punishment procedure, but did not influence responding for 60% sucrose solution under PR procedure. In addition, the forced-swim stress also elevated anxiety level of rats in an open area test. CONCLUSIONS: Acute stress induced hedonic but not motivational deficit for sucrose reward in protracted drug-abstinent animals. Additional negative emotional states besides anhedonia were evoked by acute stress.
BACKGROUND: Negative affective states, e.g., anhedonia, may be linked to the long-lasting motivational processes associated with relapse. Here, this study investigated whether, and how, anhedonic states are influenced by stressful events that contribute to craving and relapse. METHODS: All male rats were pretreated with a binge-like morphine paradigm for five days. After 12 to 16 days of withdrawal, rats were subjected to a one-hour free consumption test or three operant tasks with increasing cost/benefit ratio, i.e., fixed ratio 1 (FR1), progressive ratio (PR), and PR-punishment procedure of reinforcement, with sucrose solutions of three concentrations (4%, 15%, and 60%) as rewards. The consumption and operant responses under FR1 and PR procedures were measured following exposure to acute foot-shock stress (intermittent foot shock, 0.5 mA × 0.5 s × 10 min; mean intershock interval, 40 s), and the operant responses for 60% sucrose solution under PR-punishment procedure was measured following a forced-swim stress (5 minutes). RESULT: Foot-shock stress increased water consumption in a subpopulation of rats and decreased consumption of sucrose solutions, while it did not influence the operant responses for sucrose solutions under either FR1 or PR procedure. The forced-swim stress reduced operant responses for 60% sucrose solution under PR-punishment procedure, but did not influence responding for 60% sucrose solution under PR procedure. In addition, the forced-swim stress also elevated anxiety level of rats in an open area test. CONCLUSIONS: Acute stress induced hedonic but not motivational deficit for sucrose reward in protracted drug-abstinent animals. Additional negative emotional states besides anhedonia were evoked by acute stress.
Authors: Francisco Aguilar de Arcos; Antonio Verdejo-García; María Isabel Peralta-Ramírez; María Sánchez-Barrera; Miguel Pérez-García Journal: Drug Alcohol Depend Date: 2004-12-29 Impact factor: 4.492