Files F J, Lewis R S, Samson H H
Department of Physiology and Pharmacology, Bowman Gray School of Medicine, Winston-Salem, NC 27157-1083.
Alcohol. 1994 Nov-Dec;11(6):523-31. doi: 10.1016/0741-8329(94)90079-5.
Eight male, experimentally naive Long-Evans rats were housed in operant chambers 23 h per day following initiation to self-administer ethanol. While housed in the chambers, the animals had continuous access to food pellets according to a fixed ratio 1 schedule of reinforcement, 10% ethanol (v/v) according to a fixed ratio 4 schedule of reinforcement and water in a drinking tube with licks recorded via a drinkometer. Over a series of experimental phases, daily availability of the ethanol solution was limited to 16, 6, 4, 2, or 1 30-min period per day. The 1 30-min period access was examined during the 12th hour or the second hour of the daily sessions. Over the course of the experiment, total responses on the lever that operated the dipper, g/kg per day and number of ethanol drinking bouts per day decreased significantly as the number of daily access periods decreased. On the other hand, the number of dippers presented per ethanol bout, g/kg per ethanol bout and ethanol bout duration increased, with significant increases in dippers per bout occurring when one 30-min access period per day was provided. These data indicate that the size of a single ethanol drinking bout can be increased somewhat by limiting the opportunity to obtain ethanol reinforcement and agrees with earlier research that has shown similar effects.
八只从未接受过实验的雄性Long-Evans大鼠，在开始自行摄入乙醇后，每天在操作性条件反射箱中饲养23小时。在箱内饲养期间，动物们根据固定比率1的强化程序持续获取食物颗粒，根据固定比率4的强化程序获取10%（体积/体积）的乙醇，并通过饮水计记录舔饮饮水管中的水的次数。在一系列实验阶段中，乙醇溶液的每日供应时间限制为每天1个、2个、4个、6个或16个30分钟时间段。在每日实验时段的第12小时或第2小时对1个30分钟时间段的获取情况进行检查。在实验过程中，随着每日获取时间段数量的减少，操作水斗的杠杆上的总反应次数、每天每千克体重的反应次数以及每天乙醇饮用量的次数显著减少。另一方面，每次乙醇饮用发作时提供的水斗数量、每次乙醇饮用发作时每千克体重的饮用量以及乙醇饮用发作持续时间增加，当每天提供1个30分钟获取时间段时，每次发作的水斗数量显著增加。这些数据表明，通过限制获得乙醇强化的机会，可以在一定程度上增加单次乙醇饮用发作的量，这与早期显示类似效果的研究结果一致。
