Copyright © 2004 Priya ShahParkinson's Disease (PD), a devastating illness, occurs in one of every 100 people over 65.
It is a slowly progressing disease of
nervous system that results in progressive destruction of brain cells (neurons) in an area of brain called substantia nigra. Death occurs usually as a result of secondary complications such as infection.
One of mechanisms known to destroy neurons is damage by free radicals or reactive oxygen species - destructive molecules produced by oxidation of neurotransmitter dopamine.
The Role of Dopamine
The cells of substantia nigra use dopamine - a chemical messenger between brain or nerve cells - to communicate with cells in another region of brain called striatum.
When nigral cells are lost, nigral dopamine levels fall, resulting in a decrease in striatal dopamine.
The typical symptoms of PD - motor function deficiencies characterized by muscle rigidity, jerky movements, rhythmic resting tremors - are result of low levels of striatal dopamine.
Most dopaminergic drugs used to treat PD, are aimed at temporarily replenishing or mimicking dopamine. They improve some symptoms, but do not restore normal brain function nor halt brain cell destruction.
Dopaminergic drugs are generally effective at first in reducing many PD symptoms, but over time they lose their effect.
They also cause severe side effects because they overstimulate nerve cells elsewhere in body and cause confusion, hallucinations, nausea and fluctuations in movement of limbs.
The Role of Antioxidants
When dopaminergic neurons are lost in course of Parkinson's disease, metabolism of dopamine is increased - which in turn increases formation of highly neurotoxic hydroxyl radicals.
The most important free radical scavenger in cells of substantia nigra is powerful brain antioxidant, glutathione. Glutathione levels in PD patients are low.
And as we age, levels of glutathione in dopaminergic neurons of substantia nigra decreases. This appears to hasten cell death and advance progression of PD.
At least 80 percent of substantia nigra cells are lost before symptoms of Parkinson's disease become apparent. This is why it becomes essential to protect or maintain these cells under oxidative stress.
How does Glutathione help in Parkinson's Disease?
Several factors explain why glutathione is so beneficial in Parkinson’s disease.
1. Glutathione increases sensitivity of brain to dopamine. So although glutathione doesn't raise dopamine levels, it allows dopamine in brain to be more effective.
2. Glutathione's powerful antioxidant activity protects brain from free radical damage.
