Rice R C, Baratta A M, Farris S P
bioRxiv. 2023 Mar 24:2023.03.22.533844. doi: 10.1101/2023.03.22.533844.
Free-choice paradigms such as two-bottle choice (2BC) are commonly used to characterize ethanol consumption and preference of rodent models used to study alcohol use disorder (AUD). However, these assays are limited by low temporal resolution that misses finer patterns of drinking behavior, including circadian drinking patterns that are known to vary with age and sex and are affected in AUD pathogenesis. Modern, cost-effective tools are becoming widely available that could elucidate these patterns, including open-source, Arduino-based home-cage sipper devices. We hypothesized that adaptation of these home-cage sipper devices would uncover distinct age- and sex-related differences in temporal drinking patterns. To test this hypothesis, we used the sipper devices in a continuous 2BC paradigm using water and ethanol (10%; v/v) for 14 days to measure drinking patterns of male and female adolescent (3-week), young adult (6-week), and mature adult (18-week) C57BL/6J mice. Daily grams of fluid consumption were manually recorded at the beginning of the dark cycle, while home-cage sipper devices continuously recorded the number of sips. Consistent with prior studies, females consumed more ethanol than males, and adolescent mice consumed the most out of any age group. Correlation analyses of manually recorded fluid consumption versus home-cage sipper activity revealed a statistically significant prediction of fluid consumption across all experimental groups. Sipper activity was able to capture subtle circadian differences between experimental groups, as well as distinct individual variation in drinking behavior among animals. Blood ethanol concentrations were significantly correlated with sipper data, suggesting that home-cage sipper devices can accurately determine individual timing of ethanol consumption. Overall, our studies show that augmenting the 2BC drinking paradigm with automated home-cage sipper devices can accurately measure ethanol consumption across sexes and age groups, revealing individual differences and temporal patterns of ethanol drinking behavior. Future studies utilizing these home-cage sipper devices will further dissect circadian patterns for age and sex relevant to the pathogenesis of AUD, as well as underlying molecular mechanisms for patterns in ethanol consumption.
Female mice consume more ethanol than males in a continuous access paradigmAdolescent male and female mice consume more ethanol than young or mature adult miceAutomated home-cage sipper devices accurately measure ethanol consumptionDevices reveal sex- and age-dependent differences in circadian drinking patternsDevices reveal distinct individual variation in circadian drinking patterns.
自由选择范式，如双瓶选择（2BC），通常用于表征用于研究酒精使用障碍（AUD）的啮齿动物模型的乙醇消耗量和偏好。然而，这些检测方法受到低时间分辨率的限制，无法捕捉到更精细的饮酒行为模式，包括已知会随年龄和性别变化且在AUD发病机制中受影响的昼夜饮酒模式。现代的、具有成本效益的工具正变得广泛可用，这些工具可以阐明这些模式，包括基于开源Arduino的笼内吸管装置。我们假设，对这些笼内吸管装置进行改进将揭示出时间饮酒模式中与年龄和性别相关的明显差异。为了验证这一假设，我们在连续的2BC范式中使用水和乙醇（10%；v/v），对雄性和雌性青少年（3周龄）、年轻成年（6周龄）和成熟成年（18周龄）C57BL/6J小鼠进行了14天的实验，以测量它们的饮酒模式。在黑暗周期开始时手动记录每日液体消耗量，而笼内吸管装置则持续记录啜饮次数。与先前的研究一致，雌性比雄性消耗更多的乙醇，并且青少年小鼠在所有年龄组中消耗最多。对手动记录的液体消耗量与笼内吸管活动进行的相关性分析显示，在所有实验组中，液体消耗量具有统计学上显著的预测性。吸管活动能够捕捉实验组之间细微的昼夜差异，以及动物之间饮酒行为的明显个体差异。血液乙醇浓度与吸管数据显著相关，这表明笼内吸管装置可以准确确定乙醇消耗的个体时间。总体而言，我们的研究表明，用自动化的笼内吸管装置增强2BC饮酒范式可以准确测量不同性别和年龄组的乙醇消耗量，揭示乙醇饮酒行为的个体差异和时间模式。未来利用这些笼内吸管装置的研究将进一步剖析与AUD发病机制相关的年龄和性别的昼夜模式，以及乙醇消耗模式的潜在分子机制。
在持续获取范式中，雌性小鼠比雄性小鼠消耗更多乙醇
青少年雄性和雌性小鼠比年轻或成熟成年小鼠消耗更多乙醇
自动化的笼内吸管装置能准确测量乙醇消耗量
装置揭示了昼夜饮酒模式中性别和年龄依赖性差异
装置揭示了昼夜饮酒模式中明显的个体差异
