PARKINSON'S DISEASE

Parkinson's disease

Parkinson's disease

Introduction

Parkinson?s disease (PD) is one of the most common progressive neurodegenerative diseases in the United States. It affects approximately 0.1% of the population older than age 40, 1.0% of the population older than 65 with a mean age onset at 55 (Dauer and Przedborski, 2003, Dawson and Dawson, 2003). The cost of treatment in the Unites States between1999-2003 was estimated at $23.7 billion (Andersen, 2006). These are staggering numbers not only in terms of dollars but also in terms of human cost. PD is a very debilitating disease and decreases quality of life dramatically.

Discussion

PD is mainly the result of the loss of dopamine (DA) neurons in the substantia nigra pars compacta (SNpc) (Dawson and Dawson, 2003). The dopaminergic cell bodies in the SNpc project primarily to the putamen. These cells normally have large amounts of neuromelanin, which affords the substantia nigra its name because of the resulting pigmentation. The loss of the SNpc cells parallels a decrease in pigmentation, a hallmark of PD (Dauer and Przedborski 2003). There is a consequent decrease in the level of DA transporter (DAT) mRNA and depletion of DA is mostly in the dorsolateral putamen: where most of the nigrostriatal axons terminate.

Norepinephrine, closely related to dopamine, is the main chemical messenger of the sympathetic nervous system, the nervous system that controls many automatic body functions, such as pulse and blood pressure. The loss of norepinephrine might help explain some of the non-motor features seen in Parkinson's disease, including fatigue and abnormalities of blood pressure regulation.

The loss of DA neurons in the SNpc is only a part of the neuropathology of PD (Dawson and Dawson, 2003). Additional pathological markers of PD are the presence of neuronal proteinaceous cytoplasmic inclusions termed Lewy Bodies (LBs) and dystrophic neurites, (Lewy neurites) (Dauer and Przedborski ...