Department of Psychology, 5500 University Parkway, California State University, San Bernardino, CA 92407, USA.
Pharmacol Biochem Behav. 2013 Mar;104:154-62. doi: 10.1016/j.pbb.2013.01.016. Epub 2013 Jan 27.
The early ontogeny of D-amphetamine-induced one-trial behavioral sensitization was characterized using male and female preweanling and preadolescent rats. In Experiment 1, rats were injected with saline or D-amphetamine (1, 4, or 8mg/kg) in activity chambers or the home cage on postnatal day (PD) 12, PD 16, PD 20, or PD 24. One day later, rats were challenged with either 0.5 or 2mg/kg D-amphetamine and distance traveled was measured in activity chambers for 120min. In Experiment 2, saline or D-amphetamine was administered in activity chambers on PD 24, while a challenge injection of D-amphetamine (0.25-4mg/kg) was given on PD 25. At younger ages (PD 13 and PD 17), a strong sensitized response was evident on the test day regardless of whether rats were pretreated with D-amphetamine (4 or 8mg/kg) before being placed in the activity chamber or 30min after being returned to the home cage. Rats did not display D-amphetamine-induced behavioral sensitization on PD 21, nor was context-dependent sensitization apparent on PD 25 even when a broad dose range of D-amphetamine was used. When low doses of D-amphetamine were administered on the pretreatment and test days (1 and 0.5mg/kg, respectively), sensitized responding was not evident at any age. In summary, D-amphetamine-induced one-trial behavioral sensitization was only apparent within a narrow developmental window during early ontogeny. This ontogenetic pattern of sensitized responding is similar to the one produced by methamphetamine and distinct from the pattern produced by cocaine. The unique sensitization profiles resulting from repeated D-amphetamine and cocaine treatment may be a consequence of their different mechanisms of action.
采用雄性和雌性新生及青春期前大鼠，研究了 D-苯丙胺诱导的单次行为敏化的早期胚胎发生。在实验 1 中，在新生后第 12、16、20 或 24 天，大鼠在活动箱或其笼中分别接受生理盐水或 D-苯丙胺（1、4 或 8mg/kg）注射。一天后，大鼠接受 0.5 或 2mg/kg D-苯丙胺的挑战，并在活动箱中测量 120 分钟的运动距离。在实验 2 中，在新生后第 24 天，大鼠在活动箱中接受生理盐水或 D-苯丙胺注射，而在第 25 天，给予 D-苯丙胺（0.25-4mg/kg）的挑战注射。在年幼时（新生后第 13 和第 17 天），无论大鼠在进入活动箱之前或返回笼中 30 分钟后是否用 D-苯丙胺（4 或 8mg/kg）预处理，在测试日都表现出强烈的敏化反应。大鼠在新生后第 21 天没有表现出 D-苯丙胺诱导的行为敏化，即使使用广泛的 D-苯丙胺剂量范围，在新生后第 25 天也没有出现情境依赖性敏化。当在预处理和测试日给予低剂量的 D-苯丙胺（分别为 1 和 0.5mg/kg）时，在任何年龄都没有出现敏化反应。总之，D-苯丙胺诱导的单次行为敏化仅在早期胚胎发生的狭窄发育窗口内明显。这种敏化反应的胚胎发生模式与甲基苯丙胺产生的模式相似，与可卡因产生的模式不同。重复给予 D-苯丙胺和可卡因治疗产生的独特敏化谱可能是其不同作用机制的结果。
