Lucas L R, Schlussman S D, Ho A, McEwen B S, Kreek M J
Laboratory of Neuroendocrinology, The Rockefeller University, New York, NY 10021, USA.
Neurosci Lett. 1997 Nov 14;237(1):25-8. doi: 10.1016/s0304-3940(97)00799-4.
Incremental locomotor activity observed in behaviorally sensitized rats is associated with the activation of the mesocorticolimbic dopaminergic system and the hypothalamic-pituitary-adrenal (HPA) axis. To determine whether individual locomotor differences are altered in the behaviorally sensitized state, Long-Evans rats were placed in a novel environment and locomotor activity was recorded for 2 h. Animals, thereby, were evenly divided into two activity groups: lower- (LR) and higher- (HR) responders (LR, 367 +/- 38 cumulative beam breaks; HR, 797 +/- 43; P < 0.01). Subsequently, rats were randomly assigned to saline or chronic 'binge'-pattern (CBP) cocaine (15 mg/kg i.p., three injections/day for 14 days) treatment groups. One hour after the last injection, rats were sacrificed and trunk blood was collected for plasma corticosterone (CORT) determination. CORT levels were higher in cocaine versus saline treated animals (P < 0.01). CBP cocaine treated rats had higher locomotor activity compared to saline treated animals (P < 0.05). Moreover, rats less vulnerable to psychostimulant self-administration (LRs) appeared to have locomotor behavior resembling that of the more vulnerable phenotype (HRs) after CBP cocaine. These findings suggest that behavioral sensitization, as a result of CBP cocaine treatment, changes novelty-stress induced behavior which may reflect altered individual vulnerability to drugs of abuse.
行为致敏大鼠中观察到的渐进性运动活动与中脑皮质边缘多巴胺能系统和下丘脑-垂体-肾上腺（HPA）轴的激活有关。为了确定在行为致敏状态下个体运动差异是否发生改变，将Long-Evans大鼠置于新环境中，并记录2小时的运动活动。据此，动物被均匀分为两个活动组：低反应组（LR）和高反应组（HR）（LR，367±38次累积光束中断；HR，797±43次；P<0.01）。随后，大鼠被随机分配到生理盐水或慢性“暴饮暴食”模式（CBP）可卡因（15mg/kg腹腔注射，每天3次，共14天）治疗组。最后一次注射后1小时，处死大鼠并采集躯干血用于测定血浆皮质酮（CORT）。与生理盐水处理的动物相比，可卡因处理的动物CORT水平更高（P<0.01）。与生理盐水处理的动物相比，CBP可卡因处理的大鼠运动活动更高（P<0.05）。此外，对精神兴奋剂自我给药较不敏感的大鼠（LRs）在接受CBP可卡因处理后，其运动行为似乎与较敏感表型（HRs）相似。这些发现表明，CBP可卡因处理导致的行为致敏改变了新奇应激诱导的行为，这可能反映了个体对滥用药物的易感性改变。
