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Dopamine receptors in Parkinson's disease
1Parkinson's Disease Research Laboratory, Ottawa Civic Hospital, Ontario, Canada.
Progress in Neuro-Psychopharmacology & Biological Psychiatry
|January 1, 1988
Summary
Parkinson's disease lowers dopamine in the brain, causing compensatory increases in D1 and D2 receptors. Levodopa therapy normalizes these receptor changes.
Area of Science:
- Neuroscience
- Neurology
- Pharmacology
Background:
- Parkinson's disease (PD) is characterized by significant reductions in striatal dopamine.
- The brain attempts to compensate for dopamine loss by increasing striatal D1 and D2 receptor densities.
Purpose of the Study:
- To investigate the changes in striatal dopamine and receptor densities in Parkinson's disease.
- To examine the effects of Levodopa therapy on these neurochemical alterations.
Main Methods:
- Utilizing positron emission tomography (PET) to detect striatal changes.
- Analyzing dopamine concentrations and D1/D2 receptor densities.
Main Results:
- Observed profound decreases in striatal dopamine concentrations in Parkinson's disease.
- Documented significant increases in striatal D1 and D2 receptor densities as a compensatory response.
- Demonstrated that Levodopa therapy down-regulates both D1 and D2 receptors to normal densities.
Conclusions:
- Striatal dopamine depletion and subsequent receptor upregulation are key features of Parkinson's disease.
- Levodopa therapy effectively modulates these receptor changes, indicating its therapeutic mechanism.
- Positron emission tomography is a valuable tool for detecting early-stage Parkinson's disease and toxin-induced parkinsonism.