Oster Scott M, Toalston Jamie E, Kuc Kelly A, Pommer Tylene J, Murphy James M, Lumeng Lawrence, Bell Richard L, McBride William J, Rodd Zachary A
Department of Psychology, Purdue School of Science, Indiana University-Purdue University at Indianapolis, Indianapolis, IN 46202, USA.
Alcohol. 2006 Apr;38(3):155-64. doi: 10.1016/j.alcohol.2006.06.001.
Previously, we reported that the expression of an alcohol deprivation effect (ADE) under 24-h free-choice alcohol-drinking access in high-alcohol-drinking (HAD) replicate lines of rats is dependent upon repeated cycles of alcohol access and forced abstinence. In the present study, operant techniques (including progressive ratio measures) were used to examine the effects of initial deprivation length and number of deprivation cycles on the magnitude and duration of the ADE in HAD rats to test the hypothesis that repeated deprivations increase the reinforcing effects of ethanol. Adult male HAD-1 and HAD-2 rats were trained in two-lever operant chambers to concurrently self-administer 15% ethanol (v/v) on a fixed-ratio (FR)-5 schedule and water on an FR-1 schedule of reinforcement in daily 1-h sessions. Following 10 weeks of daily 1-h sessions, the HAD-1 and HAD-2 rats were randomly assigned to one of four groups (n=6-8/group/line): nondeprived, or deprived of alcohol for 2, 5, or 8 weeks. Following this initial period, the deprived groups were given 15% ethanol again in the operant chambers for a 2-week period, following which they were deprived again for 2 weeks (all three deprived groups). Following the fifth deprivation, the rats underwent a progressive ratio test to determine the breakpoints for the nondeprived and deprived groups. The expression of an ADE under operant conditions in HAD rats was dependent upon exposure to repeated cycles of ethanol access and abstinence. Additionally, repeated deprivations increased both the magnitude and the duration of the ADE as indicated by increased responding on the ethanol lever for more sessions. Breakpoint values for the deprived groups were 1.5-fold and twofold higher than the value for the nondeprived group for the HAD-1 and HAD-2 rats, respectively. The results suggest that repeated alcohol deprivations increased the expression of an ADE and the reinforcing effects of ethanol in both HAD replicate lines of rats, and these effects were more pronounced in the HAD-2 line than the HAD-1 line.
此前，我们报道过，在高饮酒量（HAD）大鼠重复品系中，24小时自由选择饮酒条件下酒精剥夺效应（ADE）的表达取决于酒精摄入和强制戒酒的反复循环。在本研究中，采用操作性技术（包括累进比率测量）来检验初始剥夺时长和剥夺循环次数对HAD大鼠ADE的强度和持续时间的影响，以验证反复剥夺会增加乙醇强化作用这一假设。成年雄性HAD - 1和HAD - 2大鼠在双杠杆操作性条件反射箱中接受训练，每天1小时训练时段内，按照固定比率（FR）-5程序同时自行摄入15%乙醇（v/v），并按照FR - 1强化程序摄入水。经过10周每天1小时的训练后，将HAD - 1和HAD - 2大鼠随机分为四组（每组/品系n = 6 - 8）：非剥夺组，或酒精剥夺2周、5周或8周组。在此初始阶段之后，剥夺组在操作性条件反射箱中再次给予15%乙醇，为期2周，之后再次剥夺2周（所有三个剥夺组均如此）。在第五次剥夺之后，对大鼠进行累进比率测试，以确定非剥夺组和剥夺组的断点。HAD大鼠在操作性条件下ADE的表达取决于暴露于乙醇摄入和戒酒的反复循环。此外，如乙醇杠杆上更多时段的反应增加所示，反复剥夺增加了ADE的强度和持续时间。对于HAD - 1和HAD - 2大鼠，剥夺组的断点值分别比非剥夺组高1.5倍和两倍。结果表明，反复酒精剥夺增加了大鼠两个HAD重复品系中ADE的表达以及乙醇的强化作用，且这些效应在HAD - 2品系中比HAD - 1品系中更明显。
