George F R, Ritz M C, Meisch R A
National Institute on Drug Abuse, Addiction Research Center, Baltimore, MD 21224.
Adv Alcohol Subst Abuse. 1990;9(3-4):31-42. doi: 10.1300/j251v09n03_03.
The ALKO AA and ANA rats have been selectively bred for high versus low ethanol preference, respectively. AA rats have been shown to self-administer ethanol, whereas ANA rats do not. These animals also show a range of differences on tasks which measure sensitivity to ethanol, but the relationship between ethanol intake and sensitivity to this drug in these rats is not clear. This study examined sensitivity to ethanol in AA and ANA rats as determined by ethanol's rate depressant effects on schedule controlled (Fixed-Ratio (FR) 32) responding reinforced by water deliveries. Non-drug rates of responding were similar for both lines across baseline, sham injection and vehicle conditions. Ethanol produced dose-dependent decreases in responding in both the AA and ANA rats. Dose-response curves indicated that AA rats were slightly more sensitive to the acute effects of ethanol than were ANA rats, with ED50 values of 0.52 and 0.69 g/kg for AA and ANA rats, respectively. Overall, however, the effects of ethanol on rats of responding were similar across the two lines of rats. While it is possible that constraints on behavior imposed by FR schedules could be masking underlying differences in tissue sensitivity between these animals, the results indicate that ethanol intake under preference or reinforcement conditions does not appear to be highly controlled by initial sensitivity to ethanol as measured by effects on operant performance.
ALKO AA大鼠和ANA大鼠分别被选择性培育以获得高乙醇偏好和低乙醇偏好。已证明AA大鼠会自我给药乙醇，而ANA大鼠则不会。这些动物在测量对乙醇敏感性的任务上也表现出一系列差异，但在这些大鼠中乙醇摄入量与对该药物的敏感性之间的关系尚不清楚。本研究通过乙醇对由水递送强化的定时控制（固定比率（FR）32）反应的速率抑制作用来检测AA大鼠和ANA大鼠对乙醇的敏感性。在基线、假注射和赋形剂条件下，两个品系的非药物反应速率相似。乙醇使AA大鼠和ANA大鼠的反应均出现剂量依赖性降低。剂量反应曲线表明，AA大鼠对乙醇急性作用的敏感性略高于ANA大鼠，AA大鼠和ANA大鼠的半数有效剂量（ED50）值分别为0.52和0.69 g/kg。然而，总体而言，乙醇对这两个品系大鼠反应的影响相似。虽然有可能FR时间表对行为的限制掩盖了这些动物组织敏感性的潜在差异，但结果表明，在偏好或强化条件下的乙醇摄入量似乎并不受通过对操作性行为的影响所测量的对乙醇初始敏感性的高度控制。
