Quik Maryka, Bordia Tanuja, O'Leary Kathryn
The Parkinson's Institute, Sunnyvale, CA 94089, USA.
Biochem Pharmacol. 2007 Oct 15;74(8):1224-34. doi: 10.1016/j.bcp.2007.06.015. Epub 2007 Jun 17.
Parkinson's disease is a debilitating neurodegenerative movement disorder characterized by damage to the nigrostriatal dopaminergic system. Current therapies are symptomatic only and may be accompanied by serious side effects. There is therefore a continual search for novel compounds for the treatment of Parkinson's disease symptoms, as well as to reduce or halt disease progression. Nicotine administration has been reported to improve motor deficits that arise with nigrostriatal damage in parkinsonian animals and in Parkinson's disease. In addition, nicotine protects against nigrostriatal damage in experimental models, findings that have led to the suggestion that the reduced incidence of Parkinson's disease in smokers may be due to the nicotine in tobacco. Altogether, these observations suggest that nicotine treatment may be beneficial in Parkinson's disease. Nicotine interacts with multiple nicotinic receptor (nAChR) subtypes in the peripheral and central nervous system, as well as in skeletal muscle. Work to identify the subtypes affected in Parkinson's disease is therefore critical for the development of targeted therapies. Results show that striatal alpha6beta2-containing nAChRs are particularly susceptible to nigrostriatal damage, with a decline in receptor levels that closely parallels losses in striatal dopamine. In contrast, alpha4beta2-containing nAChRs are decreased to a much smaller extent under the same conditions. These observations suggest that development of nAChR agonists or antagonists targeted to alpha6beta2-containing nAChRs may represent a particularly relevant target for Parkinson's disease therapeutics.
帕金森病是一种使人衰弱的神经退行性运动障碍,其特征是黑质纹状体多巴胺能系统受损。目前的治疗方法仅为对症治疗,且可能伴有严重的副作用。因此,人们一直在不断寻找用于治疗帕金森病症状以及减少或阻止疾病进展的新型化合物。据报道,给予尼古丁可改善帕金森病动物和帕金森病患者因黑质纹状体损伤而出现的运动功能障碍。此外,在实验模型中尼古丁可防止黑质纹状体损伤,这些研究结果提示吸烟者帕金森病发病率较低可能归因于烟草中的尼古丁。总之,这些观察结果表明尼古丁治疗可能对帕金森病有益。尼古丁在外周和中枢神经系统以及骨骼肌中与多种烟碱型受体(nAChR)亚型相互作用。因此,确定帕金森病中受影响的亚型对于开发靶向治疗至关重要。结果显示,纹状体中含α6β2的nAChR对黑质纹状体损伤特别敏感,其受体水平的下降与纹状体多巴胺的损失密切平行。相比之下,在相同条件下,含α4β2的nAChR减少的程度要小得多。这些观察结果表明,开发针对含α6β2的nAChR的nAChR激动剂或拮抗剂可能是帕金森病治疗的一个特别相关的靶点。