Ettenberg A, Geist T D
Department of Psychology, University of California, Santa Barbara 93106.
Psychopharmacology (Berl). 1991;103(4):455-61. doi: 10.1007/BF02244244.
Male albino rats were trained to traverse a straight alley for a reward of five intravenous injections of cocaine (0.75 mg/kg/injection in a volume of 0.1 ml/injection delivered over 4 s). Animals were tested one trial per day with the following dependent measures assessed on each trial: start latency, running time, the number of retreats, and the location within the alley where each retreat occurred. While start latencies remained short and stable, running times tended to increase over days. This effect was apparently related to a concomitant increase in the number of retreats occurring in the alley (r = 0.896). Retreats tended to occur in very close proximity to the goal box, suggesting that animals working for IV cocaine come to exhibit a form of conflict behavior (i.e., retreats) putatively stemming from the drug's well documented rewarding and anxiogenic properties. Consistent with this hypothesis was the demonstration that diazepam (0.5, 1.0, 2.0 mg/kg IP) pretreatment dose-dependently reduced the incidence of retreat behaviors in the alley. In addition, the rewarding efficacy of the cocaine dosing parameters was subsequently confirmed in the runway subjects by conditioned place preference. The present paradigm, therefore, provides a useful method for investigating the anxiogenic effects of self-administered cocaine in laboratory animals.
雄性白化大鼠经过训练，在一条直道上穿行以获取奖励，奖励为五次静脉注射可卡因（每次注射剂量为0.75毫克/千克，注射体积为0.1毫升，在4秒内注射完毕）。每天对动物进行一次测试，每次测试评估以下相关指标：起始潜伏期、奔跑时间、退回次数以及每次退回在直道内的位置。虽然起始潜伏期保持较短且稳定，但奔跑时间随着天数的增加而趋于延长。这种效应显然与直道内退回次数的相应增加有关（r = 0.896）。退回倾向于发生在非常靠近目标箱的位置，这表明为静脉注射可卡因而工作的动物开始表现出一种冲突行为（即退回），推测这种行为源于该药物已被充分证明的奖赏和致焦虑特性。与这一假设一致的是，有证据表明地西泮（0.5、1.0、2.0毫克/千克腹腔注射）预处理可剂量依赖性地降低直道内退回行为的发生率。此外，通过条件性位置偏爱，随后在跑道实验对象中证实了可卡因给药参数的奖赏效力。因此，本实验范式为研究实验室动物自我给药可卡因的致焦虑效应提供了一种有用的方法。
