Disorders of the Basal Nuclei
Parkinson's disease is a disorder of the basal nuclei, specifically of the substantia nigra, which releases dopamine. Parkinson's disease is the result of neurons in the substantia nigra pars compacta pathway dying. The reduction of signal through this pathway results in the tremor and other symptoms of the disease.
Parkinson's disease is neurodegenerative, meaning that neurons die that cannot be replaced, so there is no cure for the disorder. Treatments for Parkinson's disease are aimed at increasing dopamine levels in the striatum. Currently, the most common way of doing that is by providing the amino acid L-DOPA, which is a precursor to the neurotransmitter dopamine and can cross the blood-brain barrier. With levels of the precursor elevated, the remaining cells of the substantia nigra pars compacta can make more neurotransmitter and have a greater effect. Unfortunately, the patient will become less responsive to L-DOPA treatment as time progresses, and it can cause increased dopamine levels elsewhere in the brain, which are associated with psychosis or schizophrenia.
View the information on Parkinson Disease (opens in new window) for a more thorough explanation of Parkinson's disease.
