Division of Neuroscience, Oregon National Primate Research Center, Oregon Health & Science University, L-584, 505 NW 185th Avenue, Beaverton, OR 97006, USA.
Alcohol. 2014 May;48(3):265-76. doi: 10.1016/j.alcohol.2014.01.005. Epub 2014 Feb 28.
Schedule-induced polydipsia (SIP) is generated by subjecting a highly motivated animal to a sub-optimal rate of food reinforcement while also providing access to a fluid. SIP is one of several adjunctive (or displacement) behaviors that are expressed in an exaggerated form that is deemed 'excessive.' This feature makes SIP an attractive model for studying an excessive ethanol drinking phenotype in rodents. Multiple experimental variables are crucial for the full manifestation of adjunctive drinking, including the degree of food deprivation, the inter-pellet interval selected, and the size of the food reward offered. Although these variables were extensively studied and optimized for water polydipsia in rats, a similarly customized approach to ethanol SIP and application of the procedure in mice have largely been curtailed in favor of the default variable values historically used for water SIP in rats. Further, ethanol SIP also requires careful consideration of variables such as taste and ethanol concentration. Investigation of the stress axis and neurochemical systems such as dopamine and serotonin in mediating adjunctive drinking stemmed from two leading hypotheses regarding the underlying mechanisms of SIP generation: 1) SIP as a coping strategy to mitigate stress associated with the aversive environmental condition, and 2) SIP as a displacement of reward in a highly motivated animal. Ethanol SIP is a powerful model of excessive intake because it can generate an ethanol-dependent state and sustain frequent and intoxicating levels of blood ethanol with voluntary oral consumption. The required food deprivation and the loss of the excessive drinking phenotype following removal of the generator schedule are the two main limitations of the model. Future utility of ethanol SIP will be enhanced by more fully dissecting the underlying hormonal and neurochemical mechanisms and optimizing experimental variables for ethanol SIP on a per species and strain basis.
译文：
诱导性多饮症（SIP）是通过使高度活跃的动物在接受非最佳食物强化率的同时提供液体来产生的。SIP 是几种辅助（或替代）行为之一，这些行为以被认为“过度”的夸张形式表现出来。这种特征使 SIP 成为研究啮齿动物过度乙醇饮用表型的有吸引力的模型。多个实验变量对于辅助性饮酒的完全表现至关重要，包括食物剥夺的程度、选择的颗粒间间隔以及提供的食物奖励的大小。尽管这些变量在大鼠的水多饮症中进行了广泛的研究和优化，但在乙醇 SIP 方面，以及在小鼠中应用该程序的类似定制方法，在很大程度上已经被削减，以支持历史上用于大鼠水 SIP 的默认变量值。此外，乙醇 SIP 还需要仔细考虑味道和乙醇浓度等变量。在调节辅助性饮酒方面，对应激轴和神经化学系统（如多巴胺和血清素）的研究源于 SIP 生成的潜在机制的两个主要假设：1）SIP 作为一种应对策略，减轻与恶劣环境条件相关的应激，以及 2）SIP 作为高度活跃动物的奖励替代物。乙醇 SIP 是一种强大的过度摄入模型，因为它可以产生乙醇依赖性状态，并通过自愿口服消耗维持频繁和醉酒的血液乙醇水平。该模型的两个主要限制因素是所需的食物剥夺和消除生成器方案后过度饮酒表型的丧失。通过更充分地剖析潜在的激素和神经化学机制，并针对每种物种和品系优化乙醇 SIP 的实验变量，乙醇 SIP 的未来应用将得到增强。
