帕金森病是由于脑内黑质多巴胺能神经元丢失引起多巴胺减少,导致患者出现肌强直、震颤和行动迟缓等一系列症状。药物治疗是帕金森病的主要治疗方法。补充脑内多巴胺是治疗帕金森病最常用且有效的办法。多巴胺不能通过血脑屏障,但可通过补充其前体-左旋多巴,于脑内脱羧变成多巴胺。但左旋多巴进入体循环后,仅1%能进入脑内,99%在外周脱羧变成多巴胺,刺激外周多巴胺受体而引起恶心、呕吐、血压降 Parkinson’s disease is due to loss of dopaminergic neurons in the substantia nigra of the brain, which leads to a series of symptoms such as muscle rigidity, tremor and slowness of movement. Medical treatment is the main treatment for Parkinson’s disease. The addition of dopamine in the brain is the most common and effective way to treat Parkinson’s disease. Dopamine does not cross the blood-brain barrier but decarboxylates to dopamine in the brain by replenishing its precursor, levodopa. But levodopa into the systemic circulation, only 1% can enter the brain, 99% in the peripheral decarboxylation into dopamine, stimulate the peripheral dopamine receptors and cause nausea, vomiting, blood pressure