Overview of Parkinson's Disease

Study Notes

Parkinson's disease is a progressive neurodegenerative disorder that primarily impacts movement.
It results from the loss of dopamine-producing neurons in the substantia nigra, part of the basal ganglia.

Characterized as a progressive neurodegenerative disorder affecting dopaminergic neurons.
Distinct from Alzheimer's disease, which primarily impacts memory.

Basal ganglia consist of subcortical brain regions crucial for movement coordination.
Key nuclei affected in Parkinson's include the substantia nigra and striatum.
Direct Pathway:
- Involves dopaminergic signaling from the substantia nigra to the striatum.
- Dopamine release facilitates the transmission of movement commands through the thalamus to the cortex.
Indirect Pathway:
- Modulates or decreases movement by involving other neurons in the basal ganglia.

In Parkinson's, the direct pathway's effectiveness decreases due to reduced dopamine levels, resulting in bradykinesia.
Lewy bodies (protein clumps) disrupt neuronal signaling in the nigrostriatal pathway, leading to motor dysfunction.

Composed of α-synuclein protein, their accumulation disrupts normal cell signaling.
Neuronal demise accelerates when approximately 80% of neurons in the nigrostriatal pathway are affected, manifesting symptoms like rigidity and tremors.

Parkinson's disease can progress to affect additional brain regions, potentially leading to dementia.
The exact role of Lewy bodies in the disease process is still under investigation.
Most Parkinson's cases are idiopathic; about 15% show genetic predisposition.

Pesticide exposure among agricultural workers linked to higher Parkinson’s incidence.
Exposure to cleaning chemicals and heavy metals may elevate risk.
History of concussions has been associated with Parkinson's and dementia rates.
Gender-based risk: More prevalent in males than females.