Nowak K L, McKinzie D L, McBride W J, Murphy J M
Department of Psychiatry, Institute of Psychiatric Research, Indiana University School of Medicine, Indianapolis, USA.
Alcohol. 1999 Aug;19(1):85-96. doi: 10.1016/s0741-8329(99)00028-2.
Patterns of drinking and responding for ethanol (EtOH) and saccharin (SACC) were examined in the alcohol-preferring P rat using various limited-access paradigms. Adult female P rats (n = 10-20) were given 2-h access to EtOH (10-13% v/v) and SACC (0.0125% g/v) concurrently each day, or each solution individually on alternate days. Total 2-h SACC intake was significantly greater than EtOH under both concurrent (12+/-2 vs. 7+/-0.8 ml, p<0.05) and alternate-day access (18+/-1.6 vs. 10+/-0.5 ml) conditions. Under both conditions, however, EtOH intake (over 55% of the total) in the first 15 min was significantly greater than that of SACC (<25% of total). In an operant paradigm, total responding for EtOH (124+/-29) and SACC (114+/-7) under 2-h alternate-day conditions did not differ, but 65% of total EtOH responding occurred during the first 20 min versus less than 45% for SACC (p<0.05). Increasing response requirements (FR-1 to FR-5) did not significantly alter the total number of EtOH reinforcements, but decreased the total number of SACC reinforcements by approximately 50% (p<0.05). Increasing the EtOH concentration from 15% to 35% decreased the number of reinforcements approximately 50% but did not decrease the estimated g/kg EtOH intake. Increasing the SACC concentration from 0.0125% to 0.05%, however, nearly doubled the number of reinforcements. The greater preference for EtOH versus SACC during the initial part of the access period, together with the maintenance of EtOH intake in g/kg when the response requirements and the EtOH concentration were increased, suggests that EtOH intake is motivated by pharmacological consequences. Therefore, different motivational factors appear to underlie EtOH and SACC intake of the P rat. Furthermore, the pattern of EtOH intake and responding displayed by the P rat may be the result of a "bout-" or "binge-" like loss of control under restricted EtOH access conditions.
使用各种有限接触范式，在酒精偏好型P大鼠中研究了对乙醇（EtOH）和糖精（SACC）的饮用及反应模式。成年雌性P大鼠（n = 10 - 20）每天有2小时同时接触EtOH（10 - 13% v/v）和SACC（0.0125% g/v）的机会，或者隔天分别接触每种溶液。在同时接触（12±2对7±0.8毫升，p<0.05）和隔天接触（18±1.6对10±0.5毫升）条件下，2小时内SACC的总摄入量均显著高于EtOH。然而，在这两种条件下，最初15分钟内EtOH的摄入量（超过总量的55%）均显著高于SACC（<总量的25%）。在操作性范式中，在2小时隔天接触条件下，对EtOH（124±29）和SACC（114±7）的总反应量没有差异，但EtOH总反应量的65%发生在最初20分钟内，而SACC的这一比例不到45%（p<0.05）。增加反应要求（从FR - 1到FR - 5）并未显著改变EtOH强化的总数，但使SACC强化的总数减少了约50%（p<0.05）。将EtOH浓度从15%提高到35%，强化次数减少了约50%，但并未降低估计的g/kg EtOH摄入量。然而，将SACC浓度从0.0125%提高到0.05%，强化次数几乎增加了一倍。在接触期开始部分对EtOH的偏好高于SACC，以及当反应要求和EtOH浓度增加时g/kg EtOH摄入量的维持，表明EtOH摄入是由药理作用驱动的。因此，不同的动机因素似乎是P大鼠EtOH和SACC摄入的基础。此外，P大鼠表现出的EtOH摄入和反应模式可能是在有限EtOH接触条件下“发作性”或“暴饮性”失控的结果。
