Grimm Jeffrey W, Sauter Frances, MacDougall Derek, Spaulding Emily, Giadone Sarah, Stensgaard Kyra, Hardy Mason
Department of Psychology, Program in Behavioral Neuroscience, Western Washington University, Bellingham, WA 98225-9172, USA.
Department of Psychology, Program in Behavioral Neuroscience, Western Washington University, Bellingham, WA 98225-9172, USA.
Physiol Behav. 2025 Mar 15;291:114810. doi: 10.1016/j.physbeh.2025.114810. Epub 2025 Jan 10.
There are clinically significant sex differences in addiction behaviors. We have previously reported robust sex differences in motivation to consume sucrose in adult Long-Evans rats. In the present study, motivation to consume 10 % sucrose was assessed with lever press responding (0.4 mL per reinforcement) on a progressive ratio (PR) schedule during daily 3-h sessions for 1 week following either overnight (acute) or 1 month (chronic) environmental enrichment (EE). Acute EE was provided immediately after initial training or after 29 days of abstinence. Males and females were segregated by sex throughout the study. Females responded to higher breakpoints during training and post-EE testing. In both sexes, there was an abstinence-dependent increase (incubation) of PR responding for sucrose in control subjects tested after 1 month vs. 1 day of abstinence. Both acute and chronic EE decreased subsequent breakpoints, but the persistence of the effect differed by sex and length of abstinence. For testing following 1 day of abstinence from sucrose, acute EE with males resulted in decreased breakpoints persisting 3 days. EE-induced reductions in breakpoints for females were not statistically significant. For testing starting after 29 days of abstinence from sucrose, acute EE with males resulted in decreased breakpoints persisting 3 days. Chronic EE with males decreased their breakpoints for 3 days but had no effect on responding by females. EE-induced reductions in breakpoints for females were not statistically significant. Sucrose consumption relative to body weight was reduced by EE for males similar to decreases in breakpoints. For females, acute (both early and late abstinence) and chronic EE also reduced sucrose consumption, but only on the first day of testing. These results replicate our previous findings of greater motivation to consume sucrose by females, demonstrate an incubation of PR responding for both sexes, and an overall more persistent anti-sucrose taking effect of EE with males.
成瘾行为存在具有临床意义的性别差异。我们之前报道过成年Long-Evans大鼠在蔗糖消费动机方面存在显著的性别差异。在本研究中，在经过过夜（急性）或1个月（慢性）环境富集（EE）后的1周内，每天进行3小时的实验，通过在累进比率（PR）程序上的杠杆按压反应（每次强化0.4毫升）来评估10%蔗糖的消费动机。急性EE在初始训练后或禁欲29天后立即提供。在整个研究过程中，雄性和雌性按性别分开。雌性在训练和EE后测试期间对更高的断点做出反应。在对照受试者中，与禁欲1天相比，禁欲1个月后测试，两性对蔗糖的PR反应均有禁欲依赖性增加（潜伏期）。急性和慢性EE均降低了随后的断点，但效果的持续性因性别和禁欲时间长度而异。对于蔗糖禁欲1天后的测试，雄性的急性EE导致断点降低并持续3天。EE引起的雌性断点降低无统计学意义。对于蔗糖禁欲29天后开始的测试，雄性的急性EE导致断点降低并持续3天。雄性的慢性EE使其断点降低了3天，但对雌性的反应没有影响。EE引起的雌性断点降低无统计学意义。与断点降低类似，EE使雄性相对于体重的蔗糖消耗量减少。对于雌性，急性（早期和晚期禁欲）和慢性EE也降低了蔗糖消耗量，但仅在测试的第一天。这些结果重复了我们之前关于雌性对蔗糖消费动机更强的发现，证明了两性PR反应的潜伏期，以及EE对雄性总体上更持久的抗蔗糖摄取作用。
