Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, Oregon, USA.
Alcohol Clin Exp Res. 2011 Oct;35(10):1884-90. doi: 10.1111/j.1530-0277.2011.01533.x. Epub 2011 May 16.
Peer interactions can have important effects on alcohol-drinking levels, in some cases increasing use, and in other cases preventing it. In a previous study, we have established the prairie vole as a model animal for the effects of social relationships on alcohol intake and have observed a correlation of alcohol intake between individual voles housed together as pairs. Here, we investigated this correlated drinking behavior, hypothesizing that 1 animal alters its alcohol intake to match the drinking of its partner.
Adult prairie voles were tested for baseline drinking levels with continuous access to 10% alcohol and water for 4 days. In Experiment 1, high alcohol drinkers (>9 g/kg/d) were paired with low alcohol drinkers (<5 g/kg/d) of the same sex on either side of a mesh divider for 4 days with continuous access to the same 2-bottle choice test. In Experiment 2, high drinkers were paired with high drinkers and low drinkers paired with low drinkers. In both experiments, animals were again separated following pairing, and drinking was retested in isolation. In Experiment 3, alcohol-naïve animals were tested for saccharin consumption (0.05%) first in isolation and then in high saccharin drinkers paired with low saccharin drinkers, and then in another isolation period.
In Experiment 1, high drinkers paired with low drinkers significantly decreased their alcohol intake and preference from baseline drinking in isolation, and drinking levels remained significantly lower during isolation following pairing. Interestingly, there was variability between pairs in whether the high drinker decreased or the low drinker increased intake. In Experiment 2, high drinkers paired with high drinkers did not significantly change their intake level or preference, nor did low drinkers paired with low drinkers, and no changes occurred during the subsequent isolation. In Experiment 3, there was no change in saccharin intake or preference when high drinkers were paired with high drinkers or low paired with low, or in the subsequent isolation.
Alcohol drinking of prairie voles can be altered under social conditions, such that 1 animal changes its alcohol intake to more closely match the intake of the other animal, helping to explain previous findings of correlated alcohol drinking. The effect does not extend to saccharin, a naturally rewarding sweet substance. This behavior can be used to model the peer pressure that can often affect alcohol intake in humans.
同伴间的相互作用会对饮酒水平产生重要影响，有时会增加饮酒量，而有时则会防止饮酒。在之前的一项研究中，我们已将草原田鼠确立为研究社交关系对酒精摄入影响的模型动物，并观察到共同饲养的个体田鼠之间存在酒精摄入的相关性。在此，我们研究了这种相关的饮酒行为，假设 1 只动物会改变其酒精摄入量以与同伴的饮酒量相匹配。
成年草原田鼠连续 4 天通过双瓶选择测试接受 10%酒精和水的连续自由摄入，以评估其基础饮酒水平。在实验 1 中，高酒精摄入量 (>9 g/kg/d)的个体与低酒精摄入量 (<5 g/kg/d)的同性别个体在网格分隔器的两侧配对 4 天，以接受相同的 2 瓶选择测试。在实验 2 中，高饮酒量的个体与高饮酒量的个体配对，低饮酒量的个体与低饮酒量的个体配对。在这两个实验中，配对后动物再次被分开，并在单独隔离时再次进行饮酒测试。在实验 3 中，首先将酒精-naive 动物在单独状态下测试其对蔗糖的消耗（0.05%），然后将高蔗糖消耗者与低蔗糖消耗者配对，并在另一个单独隔离期进行测试。
在实验 1 中，与低饮酒量个体配对的高饮酒量个体从单独隔离时的基础饮酒量显著降低了其酒精摄入量和偏好，并且配对后在单独隔离时的饮酒量仍然显著降低。有趣的是，在配对中，高饮酒量个体是减少了摄入还是低饮酒量个体增加了摄入存在个体差异。在实验 2 中，与高饮酒量个体配对的高饮酒量个体的摄入量或偏好没有显著变化，与低饮酒量个体配对的低饮酒量个体也没有显著变化，随后的单独隔离期也没有变化。在实验 3 中，当高饮酒量个体与高饮酒量个体配对或低饮酒量个体与低饮酒量个体配对时，高饮酒量个体的蔗糖摄入量或偏好没有变化，或者在随后的单独隔离期也没有变化。
草原田鼠的酒精摄入量可以在社交条件下发生改变，从而使 1 只动物改变其酒精摄入量以更接近另 1 只动物的摄入量，这有助于解释之前发现的相关饮酒行为。这种效应不会扩展到蔗糖，蔗糖是一种天然的甜味物质。这种行为可用于模拟经常影响人类酒精摄入的同伴压力。
