Incentives to promote drinking (“happy hour”) can encourage faster rates of alcohol consumption, especially in women. Sex differences in drinking dynamics may underlie differential health vulnerabilities relating to alcohol in women versus men. Herein, we used operant procedures to model the happy hour effect and gain insight into the alcohol drinking dynamics of male and female rats. Adult male and female Wistar rats underwent operant training to promote voluntary drinking of 10% (w/v) alcohol (8 rats/sex). We tested how drinking patterns changed after manipulating the effort required for alcohol (fixed ratio, FR), as well as the length of time in which rats had access to alcohol (self-administration session length). Rats were tested twice within the 12 h of the dark cycle, first at 2 h (early phase of the dark cycle, “early sessions”) and then again at 10 h into the dark cycle (late phase of the dark cycle, “late sessions”) with an 8-h break between the two sessions in the home cage. Adult females consumed significantly more alcohol (g/kg) than males in the 30-min sessions with the FR1 schedule of reinforcement when tested late in the dark cycle. Front-loading of alcohol was the primary factor driving higher consumption in females. Changing the schedule of reinforcement from FR1 to FR3 reduced total consumption. Notably, this manipulation had minimal effect on front-loading behavior in females, whereas front-loading behavior was significantly reduced in males when more effort was required to access alcohol. Compressing drinking access to 15 min to model a happy hour drove up front-loading behavior, generating alcohol drinking patterns in males that were similar to patterns in females (faster drinking and higher intake). This strategy could be useful for exploring sex differences in the neural mechanisms underlying alcohol drinking and related health vulnerabilities. Our findings also highlight the importance of the time of testing for detecting sex differences in drinking behavior.

中文翻译：

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缩短获得酒精的时间会增加前载行为，使雄性大鼠的消费量达到雌性水平

促进饮酒（“欢乐时光”）的激励措施可以鼓励更快的饮酒率，尤其是女性。饮酒动态的性别差异可能是女性与男性与酒精相关的不同健康脆弱性的基础。在此，我们使用操作性程序来模拟欢乐时光效应，并深入了解雄性和雌性大鼠的饮酒动态。成年雄性和雌性 Wistar 大鼠接受操作训练以促进自愿饮用 10% (w/v) 酒精（8 只大鼠/性别）。我们测试了在控制酒精所需的努力（固定比率，FR）后饮酒模式如何变化，以及大鼠接触酒精的时间长度（自我管理会话长度）。在黑暗循环的 12 小时内对大鼠进行了两次测试，第一次是在 2 小时（黑暗循环的早期阶段，“早期会议”），然后在 10 小时再次进入黑暗周期（黑暗周期的后期，“晚期会议”），两次会议之间在主笼中休息 8 小时。在黑暗周期后期进行测试时，成年女性在 30 分钟的训练中消耗的酒精 (g/kg) 明显多于男性，使用 FR1 强化计划。提前饮酒是推动女性消费量增加的主要因素。将强化计划从 FR1 更改为 FR3 减少了总消耗。值得注意的是，这种操作对女性的前倾行为影响很小，而当需要更多努力获取酒精时，男性的前倾行为显着减少。将饮酒时间压缩到 15 分钟以模拟欢乐时光，从而增加了前装行为，在男性中产生与女性相似的饮酒模式（饮酒速度更快，摄入量更高）。这种策略可能有助于探索饮酒和相关健康脆弱性背后的神经机制中的性别差异。我们的研究结果还强调了检测饮酒行为性别差异的测试时间的重要性。