Quadros I M H, Souza-Formigoni M L O, Fornari R V, Nobrega J N, Oliveira M G M
Psychobiology Department, Federal University of São Paulo (UNIFESP), São Paulo, Brazil.
Behav Pharmacol. 2003 Mar;14(2):129-36. doi: 10.1097/00008877-200303000-00004.
Behavioral sensitization to drugs of abuse seems to involve learning processes. In mice, ethanol-induced locomotor sensitization is potentiated by repeated pairing of ethanol (EtOH) injections and the testing chamber. The present study aimed to test: (1). the association between the performance in a contextual conditioning task and the development of behavioral sensitization to EtOH in mice; (2). whether EtOH sensitization would be expressed in a different testing environment. Male albino Swiss mice (n=72) were initially submitted to a contextual fear conditioning task. After 2 weeks without manipulation, the animals received daily i.p. injections of 2.2 g/kg EtOH (n=52) or saline (n=20), for 21 days. They were tested weekly for locomotor activity in activity cages. After 1 week of withdrawal, all mice received 2.2 g/kg EtOH and had their locomotor activity recorded in an open-field. According to the locomotor behavior displayed along the 21-day treatment, EtOH-treated mice were classified as sensitized (n=15) or non-sensitized (n=15). When these subgroups and saline-treated mice were compared for the freezing response in the conditioning test, sensitized mice displayed a greater freezing time than non-sensitized mice. When challenged with EtOH in the open-field, none of the EtOH-treated subgroups expressed behavioral sensitization. These results suggest that the development of EtOH sensitization seems to be positively associated with contextual learning, and further confirms that the expression of sensitization is highly dependent on contextual cues.
对滥用药物的行为敏化似乎涉及学习过程。在小鼠中，乙醇诱导的运动敏化通过乙醇（EtOH）注射与测试室的重复配对而增强。本研究旨在测试：（1）情境条件任务中的表现与小鼠对EtOH行为敏化发展之间的关联；（2）EtOH敏化是否会在不同的测试环境中表现出来。雄性白化瑞士小鼠（n = 72）最初接受情境恐惧条件任务。在无操作的2周后，动物每天腹腔注射2.2 g/kg EtOH（n = 52）或生理盐水（n = 20），持续21天。每周在活动笼中测试它们的运动活动。撤药1周后，所有小鼠接受2.2 g/kg EtOH，并在旷场中记录其运动活动。根据21天治疗期间显示的运动行为，EtOH处理的小鼠被分类为敏化组（n = 15）或非敏化组（n = 15）。当比较这些亚组和生理盐水处理的小鼠在条件测试中的僵住反应时，敏化小鼠表现出比非敏化小鼠更长的僵住时间。当在旷场中用EtOH激发时，EtOH处理的亚组均未表现出行为敏化。这些结果表明，EtOH敏化的发展似乎与情境学习呈正相关，并进一步证实敏化的表达高度依赖于情境线索。
