Ellison G
Department of Psychology, University of California, Los Angeles 90024.
Brain Res. 1992 Dec 11;598(1-2):353-6. doi: 10.1016/0006-8993(92)90207-p.
Both amphetamine and cocaine lead to an intake pattern in chronic addicts in which the drug is taken repeatedly over prolonged periods. While continuously administered amphetamines, designed to mimic this intake pattern, have a neurotoxic effect on caudate dopamine terminals, several studies have failed to find similar effects following continuous cocaine. In this study, these findings in striatum were replicated in rats using silver staining for degenerating neurons. But it was further found that either amphetamine or cocaine given continuously over a 3- to 5-day period induce a highly specific pattern of axonal degeneration extending from the lateral habenular nucleus along the fasciculus retroflexus towards the ventral tegmentum. This finding supports a rich literature on the involvement of these same pathways in the actions of dopamine agonists, reward mechanisms, and the integration of limbic, extrapyramidal, and midbrain centers.
苯丙胺和可卡因都会导致慢性成瘾者形成一种用药模式，即在很长一段时间内反复使用药物。虽然旨在模拟这种用药模式的持续给予苯丙胺对尾状核多巴胺终末有神经毒性作用，但多项研究未能在持续给予可卡因后发现类似效应。在本研究中，利用银染法对变性神经元进行染色，在大鼠纹状体中重复了这些发现。但进一步发现，在3至5天的时间内持续给予苯丙胺或可卡因，都会诱导出一种高度特异性的轴突退变模式，该模式从外侧缰核沿缰核脚间束延伸至腹侧被盖区。这一发现支持了大量文献，这些文献表明这些相同的通路参与了多巴胺激动剂的作用、奖赏机制以及边缘系统、锥体外系和中脑中心的整合。
