Chester J A, Cunningham C L
Department of Behavioral Neuroscience, Oregon Health Sciences University, Portland 97201-3098, USA.
Pharmacol Biochem Behav. 1998 Jan;59(1):67-75. doi: 10.1016/s0091-3057(97)00320-1.
Several recent studies have implicated the stress hormone corticosterone in modulating the rewarding properties of abused drugs, including amphetamine and ethanol. The present experiments examined a role for corticosterone in modulating the rewarding effects of ethanol in the place conditioning paradigm. Male DBA/2J mice were subjected to a Pavlovian conditioning procedure in which a distinctive floor stimulus (CS+) was paired four times with ethanol (2 g/kg). On intervening days, a different floor stimulus was paired with saline (CS-). In the first experiment, the steroid synthesis inhibitor, aminoglutethimide (AMG), administered prior to conditioning trials with ethanol, did not alter the acquisition of place preference. However, during conditioning trials, ethanol-stimulated locomotor activity in the AMG-treated group was significantly higher relative to the vehicle-treated group, suggesting that corticosterone may normally inhibit ethanol-stimulated activity. Plasma corticosterone levels in AMG-treated mice were significantly lower than in vehicle-treated mice, showing that AMG effectively suppressed corticosterone release on CS+ trials. The second experiment examined the effect of AMG on the expression of conditioned ethanol place preference. AMG administration prior to the preference test did not alter the magnitude of ethanol place preference. Corticosterone levels in the AMG-treated groups were significantly reduced relative to vehicle-treated groups, which showed a higher level of corticosterone during the preference test. These findings show that manipulation of corticosterone levels in a physiological range does not alter the acquisition or expression of ethanol-induced conditioned place preference in DBA/2J mice.
最近的几项研究表明，应激激素皮质酮在调节包括苯丙胺和乙醇在内的成瘾药物的奖赏特性方面发挥作用。本实验在条件性位置偏爱范式中研究了皮质酮在调节乙醇奖赏效应中的作用。雄性DBA/2J小鼠接受经典条件反射程序，其中一种独特的地面刺激（CS+）与乙醇（2 g/kg）配对四次。在间隔日，另一种不同的地面刺激与生理盐水配对（CS-）。在第一个实验中，在乙醇条件反射试验前给予类固醇合成抑制剂氨鲁米特（AMG），并未改变位置偏爱的获得。然而，在条件反射试验期间，AMG处理组中乙醇刺激的运动活性相对于溶剂处理组显著更高，这表明皮质酮可能正常情况下会抑制乙醇刺激的活性。AMG处理小鼠的血浆皮质酮水平显著低于溶剂处理小鼠，表明AMG在CS+试验中有效抑制了皮质酮释放。第二个实验研究了AMG对条件性乙醇位置偏爱表达的影响。在偏爱测试前给予AMG并未改变乙醇位置偏爱的程度。AMG处理组的皮质酮水平相对于溶剂处理组显著降低，后者在偏爱测试期间皮质酮水平更高。这些发现表明，在生理范围内操纵皮质酮水平不会改变DBA/2J小鼠中乙醇诱导的条件性位置偏爱的获得或表达。
