Tetrabenazine Protects Brain Cells
By Paul Enderson on Jul 25, 2007 in Research
UT Southwestern Medical Center researchers have found that a drug used in some countries to treat the symptoms of Huntington’s disease actually prevents the death of brain cells in mice genetically engineered to mimic the hereditary condition.
The research sheds light on the biochemical mechanisms involved in the disease and suggests new avenues of study for preventing brain-cell death in at-risk people before symptoms appear - making the drug more important than people originally thought.
The drug, called tetrabenazine (TBZ), is commercially distributed as Xenazine or Nitoman and blocks the action of dopamine, a compound that some nerve cells use to signal others. TBZ is approved for use in several countries, but is still awaiting FDA approval in the US. It is used to treat uncontrollable muscle movements in Huntington’s and other neurological conditions.
In the study, the UT Southwestern researchers used mice that were genetically engineered to carry the mutant human gene for Huntington’s, causing symptoms and death of brain cells similar to those seen in the disease. The study focused on an area of the brain called the striatum, which plays a critical role in relaying signals concerning motion and higher thought and receives signals from several brain regions.
The striatum is primarily made up of nerve cells called medium spiny neurons, which undergo widespread death in Huntington’s. One major input to the striatum comes from an area called the substantia nigra, which controls voluntary movements and sends signals to the striatum via nerve cells that release dopamine.
The researchers conducted various coordination tests on both normal and genetically manipulated mice. Engineered mice given a drug that increased brain dopamine levels performed worse on these tasks, while TBZ protected against this effect. Most importantly, TBZ appears to reduce significantly cell loss in the striatum of the engineered mice, the scientists report.
The work was supported by the Robert A. Welch Foundation, the Huntington’s Disease Society of America, the Hereditary Disease Foundation, the HighQ Foundation and the National Institute of Neurological Disorders and Stroke.
For further (important) information, please read this page by Dr. LaVonne Veatch Goodman at the HD Drug Works site.
