Neuroscience Institute, National Research Council of Italy, Section of Cagliari, S.S. 554, km. 4,500, I-09042 Monserrato (CA), Italy.
Neuroscience Institute, National Research Council of Italy, Section of Cagliari, S.S. 554, km. 4,500, I-09042 Monserrato (CA), Italy.
Alcohol. 2014 May;48(3):301-11. doi: 10.1016/j.alcohol.2014.02.001. Epub 2014 Mar 1.
Sardinian alcohol-preferring (sP) rats have been selectively bred for high alcohol preference and consumption using the standard 2-bottle "alcohol (10%, v/v) vs. water" choice regimen with unlimited access; under this regimen, sP rats daily consume 6-7 g/kg alcohol. The present study assessed a new paradigm of alcohol intake in which sP rats were exposed to the 4-bottle "alcohol (10%, 20%, and 30%, v/v) vs. water" choice regimen during one of the 12 h of the dark phase of the daily light/dark cycle; the time of alcohol exposure was changed daily in a semi-random order and was unpredictable to rats. Alcohol intake was highly positively correlated with the time of the drinking session and averaged approximately 2 g/kg when the drinking session occurred during the 12th hour of the dark phase. Alcohol drinking during the 12th hour of the dark phase resulted in (a) blood alcohol levels averaging approximately 100 mg% and (b) severe signs of alcohol intoxication (e.g., impaired performance at a Rota-Rod task). The results of a series of additional experiments indicate that (a) both singular aspects of this paradigm (i.e., unpredictability of alcohol exposure and concurrent availability of multiple alcohol concentrations) contributed to this high alcohol intake, (b) alcohol intake followed a circadian rhythm, as it decreased progressively over the first 3 h of the light phase and then maintained constant levels until the beginning of the dark phase, and (c) sensitivity to time schedule was specific to alcohol, as it did not generalize to a highly palatable chocolate-flavored beverage. These results demonstrate that unpredictable, limited access to multiple alcohol concentrations may result in exceptionally high intakes of alcohol in sP rats, modeling - to some extent - human binge drinking. A progressively increasing emotional "distress" associated to rats' expectation of alcohol might be the neurobehavioral basis of this drinking behavior.
撒丁岛酒精偏爱（sP）大鼠通过使用标准的 2 瓶“酒精（10%，v/v）与水”选择方案和无限制的途径进行选择性繁殖，以获得高酒精偏好和消耗，在这种方案下，sP 大鼠每天消耗 6-7 g/kg 酒精。本研究评估了一种新的酒精摄入模式，其中 sP 大鼠在每日光照/黑暗周期的黑暗阶段的 12 小时中的一个小时内暴露于 4 瓶“酒精（10%、20%和 30%，v/v）与水”选择方案中；酒精暴露的时间每天以半随机的顺序改变，对大鼠来说是不可预测的。酒精摄入量与饮酒时间高度正相关，当饮酒时间发生在黑暗阶段的第 12 小时时，平均约为 2 g/kg。在黑暗阶段的第 12 小时饮酒会导致 (a) 血液酒精水平平均约为 100 mg%和 (b) 严重的酒精中毒迹象（例如，在转棒任务中表现受损）。一系列额外实验的结果表明，(a) 该范式的两个独特方面（即酒精暴露的不可预测性和同时提供多种酒精浓度）都导致了这种高酒精摄入量，(b) 酒精摄入量遵循昼夜节律，随着时间的推移逐渐减少在光阶段的前 3 小时，然后在黑暗阶段开始前保持恒定水平，(c) 对时间安排的敏感性是特异性的，因为它不会推广到高度可口的巧克力味饮料。这些结果表明，不可预测的、有限的获取多种酒精浓度可能导致 sP 大鼠异常高的酒精摄入量，在某种程度上模拟了人类的狂饮。与大鼠对酒精的期望相关的逐渐增加的情绪“困扰”可能是这种饮酒行为的神经行为基础。
