The study's findings are important because there are currently more than 2 million cocaine abusers in the US today, the researchers said. Many individuals who abused the drug during the height of the cocaine abuse epidemic of the 1970s and 1980s are now entering their older years, when symptoms of PD are likely to emerge.

A report on this work appears in the online, prepublication edition of Neuroscience.

The St. Jude team showed in laboratory models of both the adult and fetal brains that exposure to cocaine alters the nerve bodies in the region of the brain called the substantia nigra. This damage made the neurons more susceptible to MPTP, a toxin known to cause symptoms of PD.

The nigrostriatal system is a pathway of nerves that originates in the area called the substantial nigra pars compacta (SNpc) and spreads out into certain other parts of the brain. The neurons in the SNpc make the neurotransmitter dopamine, and degeneration of this area and the nigrostriatal system is one of the major hallmarks of PD, according to Richard Smeyne, Ph.D., an associate member of the St. Jude Department of Developmental Neurobiology.

"Our findings suggest that cocaine makes the SNpc in adults susceptible to further damage from environmental toxins that can cause Parkinson's disease," Smeyne said "The findings also strongly suggest that women who abuse cocaine during pregnancies put their children at an increased risk for developing Parkinson's disease."

Cocaine is also known to disrupt the normal function of the dopamine transporter, a protein that sweeps up dopamine from the synapse after it stimulates its target nerve,
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Contact: Carrie Strehlau
Carrie.Strehlau@stjude.org
901-495-2295
St. Jude Children's Research Hospital
13-Dec-2005