Lile Joshua A, Charnigo Richard J, Nader Michael A
Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC 27157-1083, USA.
Behav Pharmacol. 2013 Sep;24(5-6):482-5. doi: 10.1097/FBP.0b013e3283644d44.
Epidemiological data indicate that rates of methamphetamine misuse surpass those of D-amphetamine, but self-administration research in animals and humans has not typically demonstrated differences in their reinforcing effects. The present study used a within-session, exponentially increasing progressive-ratio schedule and extended-access conditions to assess the relative reinforcing strength of D-amphetamine and methamphetamine in rhesus monkeys (n=5) trained to self-administer cocaine. A range of doses of methamphetamine (0.003-0.1 mg/kg/injection), D-amphetamine (0.003-0.1 mg/kg/injection), and cocaine (0.003-0.3 mg/kg/injection) was tested to capture the ascending and descending limbs of the dose-effect functions. Each drug functioned as a reinforcer, but the peak number of self-administered D-amphetamine injections was significantly lower compared with methamphetamine and cocaine; the peak number of self-administered injections of cocaine and methamphetamine did not differ. Although differences in availability and other social factors likely impact relative rates of abuse, the present data suggest that the greater reinforcing strength of methamphetamine contributes to its increased use compared with D-amphetamine.
流行病学数据表明，甲基苯丙胺滥用率超过右旋苯丙胺，但动物和人类的自我给药研究通常未显示出它们在强化作用方面的差异。本研究采用会话内指数递增的渐进比率程序和延长给药条件，以评估甲基苯丙胺和右旋苯丙胺对经训练可自我给药可卡因的恒河猴（n = 5）的相对强化强度。测试了一系列剂量的甲基苯丙胺（0.003 - 0.1毫克/千克/注射）、右旋苯丙胺（0.003 - 0.1毫克/千克/注射）和可卡因（0.003 - 0.3毫克/千克/注射），以捕捉剂量效应函数的上升和下降分支。每种药物都起到了强化物的作用，但与甲基苯丙胺和可卡因相比，自我给药的右旋苯丙胺注射峰值数量显著更低；自我给药的可卡因和甲基苯丙胺注射峰值数量没有差异。尽管可获得性和其他社会因素的差异可能会影响相对滥用率，但目前的数据表明，与右旋苯丙胺相比，甲基苯丙胺更强的强化强度导致了其使用的增加。
