Carlson J, Armstrong B, Switzer R C, Ellison G
Department of Psychology, UCLA and NeuroScience Associates, Knoxville, TN, USA.
Neuropharmacology. 2000 Oct;39(13):2792-8. doi: 10.1016/s0028-3908(00)00141-6.
When administered continuously for several days at relatively low plasma levels, a variety of drugs of abuse with strong dopaminergic actions induce degeneration in axons traveling from the lateral habenula through the sheath of fasciculus retroflexus to midbrain monoaminergic nuclei. With some of these drugs, such as cocaine, this is virtually the only degeneration induced in brain. Nicotine given continuously also selectively induces degeneration in fasciculus retroflexus, but in the other half of the tract: the cholinergic axons running from medial habenula in the core of the tract to the interpeduncular nucleus. Fasciculus retroflexus appears to be a weak link in brain for diverse drugs of abuse when administered incessantly for several days. Alterations in this tract would be predicted to be especially important for the genesis of the symptomatology which develops during drug binges, residual effects of such binges, and the processes underlying relapse.
当以相对较低的血浆水平连续给药数天时，多种具有强烈多巴胺能作用的滥用药物会导致轴突发生退化，这些轴突从外侧缰核穿过缰核束鞘延伸至中脑单胺能核。对于其中一些药物，如可卡因，这几乎是大脑中唯一诱导产生的退化现象。持续给予尼古丁也会选择性地诱导缰核束发生退化，但却是在该束的另一半：即从束核心的内侧缰核延伸至脚间核的胆碱能轴突。当连续数天不间断给药时，缰核束似乎是大脑中对多种滥用药物的一个薄弱环节。预计该束的改变对于药物成瘾期间出现的症状学、此类成瘾的残留效应以及复发背后的过程的发生尤为重要。
