Understanding Parkinson's Disease

Pathophysiology of Parkinson's disease

  • The primary cause of Parkinson’s disease (PD) is a progressive degeneration of dopaminergic neurons in a part of the brain called the substantia nigra leading to a decrease in the dopamine levels in the brain. A deficit of dopamine is directly linked to the appearance of the characteristic motor symptoms. Despite intensive research, however, the cause of the degeneration remains unknown1
  • As PD progresses, the loss of dopaminergic neurons continues and motor function declines1
  • A major problem is that by the time the patient’s symptoms have been sufficiently apparent to seek treatment, about 50-80% of their dopaminergic neurons may have died2-8
The evolution of PD
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View references

  1. Fahn S. Description of Parkinson's disease as a clinical syndrome. Ann NY Acad Sci 2003; 991: 1-14.
  2. Hirsch E et al. Melanised dopaminergic neurons are differentially susceptible to degeneration in Parkinson's disease. Nature 1988; 334: 345-348.
  3. Lang AE, Obeso JA. Challenges in Parkinson's disease: restoration of the nigrostriatal dopamine system is not enough. Lancet Neurol 2004; 3: 309-316.
  4. Braak H et al. Staging of brain pathology related to sporadic Parkinson's disease. Neurobiol Aging 2003; 24: 197-211.
  5. Braak H et al. Stages in the development of Parkinson's disease related pathology. Cell Tissue Res 2004; 318: 121-134.
  6. Hornykiewicz O, Kish SJ. Biochemical pathophysiology of Parkinson's disease. Adv Neurol 1987; 45: 19-34.
  7. Riederer P, Wuketich S. Time course of nigrostriatal degeneration in Parkinson's disease. A detailed study of influential factors in human brain amine analysis. J Neural Transm 1976; 38, 277-301.
  8. Koller WC. When does Parkinson's disease begin? Neurology 1992; 42(Suppl 4): 27-31.

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