帕金森病“开-关”现象是在服用左旋多巴后出现的快速的、常不可预言的动作改变。有50～80%的帕金森病人在服用 L-多巴数年后出现这种现象。服用的 L-多巴必须通过血脑屏障从血浆中渗透到脑组织。这种通过需要一种载体介导,一切内生性大的中性氨基酸(large neutral amino acids,LNAA)如异亮氨酸等的转运亦需相同的载体介导,多巴通过时必须与 LNAA 竞争载体。病人和方法 3例男性,年龄71～76岁,患帕金 The “on-off” phenomenon of Parkinson’s disease is a rapid, often unpredictable, movement change that occurs after taking levodopa. This phenomenon occurs in 50-80% of Parkinson’s patients after taking L-dopa for several years. The L-dopa taken must penetrate from the plasma into the brain through the blood-brain barrier. This is mediated by the need for a vector that also requires the same vector for the transport of all large endogenous large neutral amino acids (LNAA), such as isoleucine, which must compete with LNAA when it passes Vector. Patients and methods 3 cases of male, aged 71 to 76 years old, suffering from Parkin