Center for Alcohol Research in Epigenetics, Department of Psychiatry, University of Illinois Chicago.
Center for Alcohol Research in Epigenetics, Department of Psychiatry, University of Illinois Chicago;
J Vis Exp. 2024 Nov 8(213). doi: 10.3791/67486.
Two-bottle choice home cage drinking is one of the most widely used paradigms to study ethanol consumption in rodents. In its simplest form, animals are provided with access to two drinking bottles, one of which contains regular tap water and the other ethanol, with daily intake measured by change in bottle weight over the 24 h period. Consequently, this approach requires no specialized laboratory equipment. While such ease of implementation is likely the greatest contributor to its widespread adoption by preclinical alcohol researchers, the resolution of drinking data acquired using this approach is limited by the number of times the researcher measures bottle weight (e.g., once daily). However, the desire to examine drinking patterns in the context of overall intake, pharmacological interventions, and neuronal manipulations has prompted the development of home cage lick detection systems that can acquire data at the level of individual licks. Although a number of these systems have been developed recently, the open-source system, LIQ HD (Lick Instance Quantifier Home cage Device), has garnered significant attention in the field for its affordability and user friendliness. Although exciting, this system was designed for use in mice. Here, we review appropriate procedures for standard and lickometer-equipped two-bottle choice home cage drinking. We also introduce methods for adapting the LIQ HD system to rats including hardware modifications to accommodate larger cage size and a redesigned 3D printed bottle holder compatible with standard off-the-shelf drinking bottles. Using this approach, researchers can examine daily drinking patterns in addition to levels of intake in many rats in parallel thereby increasing the resolution of acquired data with minimal investment in additional resources. These methods provide researchers with the flexibility to use either standard bottles or a lickometer-equipped apparatus to interrogate the neurobiological mechanisms underlying alcohol drinking depending on their precise experimental needs.
双瓶选择式笼内饮酒是研究啮齿动物乙醇消耗最广泛使用的范式之一。在最简单的形式中，动物被提供两个饮水瓶，其中一个装有普通自来水，另一个装有乙醇，通过 24 小时内瓶重的变化来测量每日摄入量。因此，这种方法不需要特殊的实验室设备。虽然这种方法易于实施可能是其被临床前酒精研究人员广泛采用的最大原因，但使用这种方法获得的饮酒数据的分辨率受到研究人员测量瓶重次数的限制（例如，每天一次）。然而，为了在整体摄入、药理学干预和神经元操作的背景下研究饮酒模式，人们开发了能够在个体舔舐水平上获取数据的笼内舔舐检测系统。尽管最近已经开发了许多这样的系统，但开源系统 LIQ HD（舔舐实例量化器笼内设备）因其价格实惠和易于使用而在该领域引起了广泛关注。虽然令人兴奋，但该系统是为小鼠设计的。在这里，我们回顾了标准和带有舔舐计的双瓶选择式笼内饮酒的适当程序。我们还介绍了将 LIQ HD 系统改编为大鼠的方法，包括对硬件进行修改以适应更大的笼子尺寸，以及重新设计与标准即用型饮水瓶兼容的 3D 打印瓶架。使用这种方法，研究人员可以在许多大鼠中同时检查每日饮酒模式和摄入量水平，从而在不增加额外资源投入的情况下提高获得数据的分辨率。这些方法为研究人员提供了根据其精确的实验需求，使用标准瓶或带有舔舐计的仪器来探究饮酒的神经生物学机制的灵活性。
