Rorick Linda M, Finn Peter R, Steinmetz Joseph E
Program in Neural Science, Department of Psychology, Indiana University, 1101 East 10th Street, Bloomington, IN 47405-7007, USA.
Pharmacol Biochem Behav. 2003 Apr;75(1):89-102. doi: 10.1016/s0091-3057(03)00046-7.
We previously reported that ethanol-naive high-alcohol-drinking (HAD1 and HAD2) rats exhibited selective deficits in active avoidance learning, as compared to low-alcohol-drinking (LAD1 and LAD2) rats, in a signaled bar-pressing task [Alcohol. Clin. Exp. Res. 24 (2000) 1778]. In the current study, we used appetitive and aversive learning tasks to assess whether administration of ethanol influences approach and avoidance learning in HAD and LAD rats. Rats were administered 0.0, 0.5, 1.0, or 1.5 g ethanol/kg body weight during appetitive and aversive conditioning sessions. We found that ethanol impaired acquisition of the appetitive conditioned response in a dose-dependent manner in both HAD and LAD rats, with 1.5 g/kg ethanol producing the greatest deficits. Notably, moderate doses of ethanol (0.5 and 1.0 g/kg) partially reversed avoidance learning deficits in HAD rats, but only when appetitive conditioning preceded aversive conditioning. The highest dose (1.5 g/kg EtOH) abolished avoidance responding altogether in HAD rats. Avoidance responding in LAD rats was not affected by any dose of ethanol. These results are consistent with previous studies suggesting that alcohol preference may be associated with increased fear or anxiety, but the conditions under which ethanol produces a reduction of fear and anxiety in HAD rats appear to be relatively complex.
我们之前报道过，在一项信号压杆任务中，与低酒精摄入量（LAD1和LAD2）的大鼠相比，初次接触乙醇的高酒精摄入量（HAD1和HAD2）大鼠在主动回避学习中表现出选择性缺陷[《酒精：临床与实验研究》24 (2000) 1778]。在当前研究中，我们使用了奖赏性和厌恶性学习任务来评估给予乙醇是否会影响HAD和LAD大鼠的趋近和回避学习。在奖赏性和厌恶性条件反射训练期间，给大鼠分别注射0.0、0.5、1.0或1.5 g乙醇/千克体重。我们发现，乙醇以剂量依赖性方式损害了HAD和LAD大鼠的奖赏性条件反应的获得，1.5 g/kg乙醇造成的缺陷最大。值得注意的是，中等剂量的乙醇（0.5和1.0 g/kg）部分逆转了HAD大鼠的回避学习缺陷，但仅当奖赏性条件反射先于厌恶性条件反射时才会出现这种情况。最高剂量（1.5 g/kg乙醇）完全消除了HAD大鼠的回避反应。任何剂量的乙醇都未影响LAD大鼠的回避反应。这些结果与之前的研究一致，表明酒精偏好可能与恐惧或焦虑增加有关，但乙醇在何种条件下会减轻HAD大鼠的恐惧和焦虑似乎相对复杂。
