DiLullo S L, Martin-Iverson M T
Department of Psychiatry, University of Alberta, Edmonton, Canada.
Brain Res. 1992 Apr 24;578(1-2):161-7. doi: 10.1016/0006-8993(92)90244-4.
Rats with a history of receiving (+)-amphetamine in a specific environment exhibit a conditioned psychomotor response when subsequently placed in that environment without drug treatment. Previous work has shown that while the unconditioned effects of amphetamine can be blocked by dopamine D1 or D2 receptor antagonists or with alpha-methyl-p-tyrosine, conditioned locomotion is not influenced by these treatments. In the present experiment, alpha-methyl-p-tyrosine (50 mg/kg, s.c.) was given in conjunction with amphetamine (1.5 mg/kg, s.c.) for 8 days before testing for conditioned locomotion. alpha-Methyl-p-tyrosine completely blocked amphetamine-induced locomotion but only attenuated amphetamine-conditioned locomotion. Reserpine (reduced over the 8 days from 2.5 to 1.25 mg/kg, i.p.) did not block amphetamine-induced locomotion; indeed, potentiation of amphetamine-induced locomotor activity was observed on the last 3 days of treatment. Reserpine treatment in conjunction with alpha-methyl-p-tyrosine treatment blocked amphetamine-induced locomotion for the first 4 days only, with full recovery of amphetamine-induced unconditioned locomotion by the last treatment day. Reserpine alone had no effect on amphetamine-conditioned locomotion, but completely blocked amphetamine-conditioned locomotion when given with alpha-methyl-p-tyrosine. It is concluded that the alpha-methyl-p-tyrosine-sensitive pool of dopamine mediates the immediate psychomotor effects of amphetamine, but that both the alpha-methyl-p-tyrosine- and reserpine-sensitive pools of dopamine are involved in the establishment of amphetamine-conditioned locomotion. In addition, the occurrence of amphetamine-conditioned locomotion is independent of the direct effects of amphetamine on locomotion.
在特定环境中接受过（+）-苯丙胺的大鼠，在随后未接受药物治疗而被置于该环境时，会表现出条件性精神运动反应。先前的研究表明，虽然苯丙胺的非条件性效应可被多巴胺D1或D2受体拮抗剂或α-甲基-p-酪氨酸阻断，但条件性运动不受这些治疗的影响。在本实验中，在测试条件性运动前8天，将α-甲基-p-酪氨酸（50毫克/千克，皮下注射）与苯丙胺（1.5毫克/千克，皮下注射）联合使用。α-甲基-p-酪氨酸完全阻断了苯丙胺诱导的运动，但仅减弱了苯丙胺条件性运动。利血平（在8天内从2.5毫克/千克腹腔注射降至1.25毫克/千克）未阻断苯丙胺诱导的运动；事实上，在治疗的最后3天观察到苯丙胺诱导的运动活性增强。利血平与α-甲基-p-酪氨酸联合治疗仅在最初4天阻断了苯丙胺诱导的运动，到最后一个治疗日时苯丙胺诱导的非条件性运动完全恢复。单独使用利血平对苯丙胺条件性运动没有影响，但与α-甲基-p-酪氨酸一起使用时完全阻断了苯丙胺条件性运动。得出的结论是，α-甲基-p-酪氨酸敏感的多巴胺池介导了苯丙胺的即时精神运动效应，但α-甲基-p-酪氨酸和利血平敏感的多巴胺池都参与了苯丙胺条件性运动的建立。此外，苯丙胺条件性运动的发生与苯丙胺对运动的直接影响无关。
