Abstract：
BACKGROUND: Intensely stressful experiences can lead to long-lasting changes in appetitive and aversive behaviors. In humans, post-traumatic stress disorder increases the risk of comorbid appetitive disorders including addiction and obesity. We have previously shown that an acute stressful experience in adult male rats suppresses motivation for natural reward.
OBJECTIVE: We examine the impact of sex and age on the effects of intense stress on action-based (instrumental) and stimulus-based (Pavlovian) motivation for natural reward (food).
METHODS: Rats received 15 unsignaled footshocks (stress) in a single session followed by appetitive training and testing in a distinct context. In Experiment 1, stress occurred in either adolescence (PN28) or adulthood (PN70) with appetitive training and testing beginning on PN71 for all rats. In Experiment 2, stress and appetitive training/testing occurred in adolescence.
RESULTS: Acute stress in adolescent females suppressed instrumental motivation assessed with progressive ratio testing when testing occurred in late adolescence or in adulthood, whereas in males stress in adolescence did not suppress instrumental motivation. Acute stress in adulthood did not alter instrumental motivation. In contrast, Pavlovian motivation assessed with single-outcome Pavlovian-to-instrumental transfer (SO-PIT) was consistently enhanced in females following adolescent or adult stress. In males, however, stress in adolescence had no effect, whereas stress in adulthood attenuated SO-PIT.
CONCLUSIONS: Acute stress in adolescence or adulthood altered instrumental motivation and stimulus-triggered Pavlovian motivation in a sex and developmentally specific manner. These findings suggest that the persistent effects of acute stress on Pavlovian and instrumental motivational processes differ in females and males, and that males may be less vulnerable to the deleterious effects of intense stress during adolescence on appetitive motivation.
OBJECTIVE: We examine the impact of sex and age on the effects of intense stress on action-based (instrumental) and stimulus-based (Pavlovian) motivation for natural reward (food).
METHODS: Rats received 15 unsignaled footshocks (stress) in a single session followed by appetitive training and testing in a distinct context. In Experiment 1, stress occurred in either adolescence (PN28) or adulthood (PN70) with appetitive training and testing beginning on PN71 for all rats. In Experiment 2, stress and appetitive training/testing occurred in adolescence.
RESULTS: Acute stress in adolescent females suppressed instrumental motivation assessed with progressive ratio testing when testing occurred in late adolescence or in adulthood, whereas in males stress in adolescence did not suppress instrumental motivation. Acute stress in adulthood did not alter instrumental motivation. In contrast, Pavlovian motivation assessed with single-outcome Pavlovian-to-instrumental transfer (SO-PIT) was consistently enhanced in females following adolescent or adult stress. In males, however, stress in adolescence had no effect, whereas stress in adulthood attenuated SO-PIT.
CONCLUSIONS: Acute stress in adolescence or adulthood altered instrumental motivation and stimulus-triggered Pavlovian motivation in a sex and developmentally specific manner. These findings suggest that the persistent effects of acute stress on Pavlovian and instrumental motivational processes differ in females and males, and that males may be less vulnerable to the deleterious effects of intense stress during adolescence on appetitive motivation.
摘要：
背景：强烈的压力经历会导致食欲和厌恶行为的长期变化。在人类中,创伤后应激障碍增加了共患食欲障碍的风险,包括成瘾和肥胖.我们以前已经证明，成年雄性大鼠的急性压力经历会抑制自然奖励的动机。
目的：我们研究了性别和年龄对强烈压力对基于行动（工具性）和基于刺激（巴甫洛夫）的自然奖励（食物）动机的影响。
方法：大鼠在一个疗程中接受了15次无信号的足电击（压力），然后在不同的环境中进行食欲训练和测试。在实验1中，压力发生在青春期（PN28）或成年期（PN70），所有大鼠的食欲训练和测试始于PN71。在实验2中，压力和食欲训练/测试发生在青春期。
结果：当测试发生在青春期后期或成年期时，通过渐进性比率测试评估青春期女性的急性压力抑制了工具动机，而在男性中，青春期的压力并没有抑制工具性动机。成年后的急性压力并没有改变工具动机。相比之下,在青少年或成人压力下，女性的Pavlovian动机通过单一结果的Pavlovian到工具转移（SO-PIT）得到了持续增强。在男性中，然而,青春期的压力没有影响，而成年期的压力减弱了SO-PIT。
结论：青春期或成年期的急性压力以性和发育特异性的方式改变了工具动机和刺激触发的巴甫洛夫动机。这些发现表明，急性应激对巴甫洛夫和工具性动机过程的持续影响在女性和男性中有所不同，男性可能不太容易受到青春期强烈压力对食欲动机的有害影响。
目的：我们研究了性别和年龄对强烈压力对基于行动（工具性）和基于刺激（巴甫洛夫）的自然奖励（食物）动机的影响。
方法：大鼠在一个疗程中接受了15次无信号的足电击（压力），然后在不同的环境中进行食欲训练和测试。在实验1中，压力发生在青春期（PN28）或成年期（PN70），所有大鼠的食欲训练和测试始于PN71。在实验2中，压力和食欲训练/测试发生在青春期。
结果：当测试发生在青春期后期或成年期时，通过渐进性比率测试评估青春期女性的急性压力抑制了工具动机，而在男性中，青春期的压力并没有抑制工具性动机。成年后的急性压力并没有改变工具动机。相比之下,在青少年或成人压力下，女性的Pavlovian动机通过单一结果的Pavlovian到工具转移（SO-PIT）得到了持续增强。在男性中，然而,青春期的压力没有影响，而成年期的压力减弱了SO-PIT。
结论：青春期或成年期的急性压力以性和发育特异性的方式改变了工具动机和刺激触发的巴甫洛夫动机。这些发现表明，急性应激对巴甫洛夫和工具性动机过程的持续影响在女性和男性中有所不同，男性可能不太容易受到青春期强烈压力对食欲动机的有害影响。
