Hughes Robert N, Hamilton Jennifer J
Department of Psychology, University of Canterbury, Christchurch, 8140, New Zealand.
Department of Psychology, University of Canterbury, Christchurch, 8140, New Zealand.
Behav Brain Res. 2018 Jun 1;345:30-38. doi: 10.1016/j.bbr.2018.02.013. Epub 2018 Feb 21.
For fourteen days, male and female PVG/c hooded rats were provided continuously with either pure drinking water, or water containing caffeine in a quantity approximating a daily dose of 31.1 mg/kg. Then at intervals of 3 days, they were administered 1, 2 mg/kg methamphetamine (MA) or saline before being tested for anxiety-related behavior in a zero maze or a light/dark box, or their short-term spatial memory was assessed in a Y maze following introduction of a novel brightness change in one of the arms. Each rat experienced each type of apparatus with the same acute MA or saline treatment while still exposed to chronic caffeine or pure drinking water. While chronic caffeine on its own did not affect any behavioral measure, acute MA was anxiolytic for male rats suggested by increased entries and occupancy of zero-maze enclosed areas, and decreased emergence latencies and increased entries into the light/dark-box light compartment. Females were less affected than males by MA in both types of apparatus unless they also consumed caffeine. For male rats, choices of the Y-maze novel arm were affected by neither caffeine nor MA, but for females provided with unadulterated water, such choices were reduced by 1 mg/kg MA but increased for those exposed to caffeine, thereby suggesting either impaired or improved memory respectively. However, changes in anxiety could also explain these results. Overall, results generated in the three types of apparatus supported potentiation by caffeine of any effects of MA on anxiety for females only.
在十四天的时间里，持续为雄性和雌性PVG/c有帽大鼠提供纯净水，或含有咖啡因的水，其含量接近每日剂量31.1毫克/千克。然后每隔3天，在零迷宫或明暗箱中对它们进行焦虑相关行为测试之前，给它们注射1、2毫克/千克甲基苯丙胺（MA）或生理盐水，或者在Y迷宫的一个臂引入新的亮度变化后，评估它们的短期空间记忆。每只大鼠在接受相同的急性MA或生理盐水处理时，都经历了每种类型的实验装置，同时仍暴露于慢性咖啡因或纯净饮用水中。虽然慢性咖啡因本身不影响任何行为指标，但急性MA对雄性大鼠具有抗焦虑作用，这表现为零迷宫封闭区域的进入次数和停留时间增加，明暗箱亮区的出现潜伏期缩短和进入次数增加。在这两种实验装置中，雌性大鼠受MA的影响比雄性大鼠小，除非它们也摄入了咖啡因。对于雄性大鼠，Y迷宫新臂的选择既不受咖啡因也不受MA的影响，但对于饮用纯净水的雌性大鼠，1毫克/千克的MA会减少这种选择，而对于接触咖啡因的雌性大鼠，这种选择会增加，从而分别表明记忆受损或改善。然而，焦虑的变化也可以解释这些结果。总体而言，在三种实验装置中产生的结果支持仅咖啡因增强MA对雌性焦虑的任何影响。
