Final answer:
Parkinson's disease involves the degeneration of nerve fibers from the cell bodies in the substantia nigra that produce dopamine, leading to motor and cognitive symptoms. Excessive glutamate neurotransmission also plays an important role in the disease progression.
Step-by-step explanation:
Parkinson's disease is characterized by the degeneration of nerve fibers originating from the cell bodies of neurons in the substantia nigra, part of the basal ganglia, which are crucial for movement control. The key neurotransmitter affected by this degeneration is dopamine, leading to motor and cognitive symptoms such as tremors, rigid muscles, and in advanced stages, dementia. Dopaminergic denervation due to this neurodegeneration results in Lewy bodies formation and, contributing to the disease pathology, excessive glutamate neurotransmission which can lead to excitotoxicity.
Medications can initially help reduce motor disturbances but may become less effective as Parkinson's advances, with side effects like involuntary movements complicating treatment. Understanding the complex interaction between neurotransmitters and the progression of neurodegeneration in Parkinson's is key to developing more effective therapies to halt or reverse the disease process.