US scientists recently discovered an old discontinued drug that reduces the mental retardation in mice with a certain form of Down syndrome, according to a study published in the journal of Nature Neuroscience.
Professor of Psychiatry and Director of the Down Syndrome Research Centre at Stanford University in California, Craig Garner, led the research. His team experimented with Ts65Dn mice bred as model test specimens for Down syndrome. Ts65Dn mice have increased inhibition of the dentate gyrus, the part of the brain near the hippocampus that is associated with learning and memory.
The mice were given a discontinued drug that was originally used for epilepsy in humans, called pentylenetetrazole or PTZ, a GABAA antagonist.
Results were positive. The mice’s ability to explore, learn and remember things improved. Their ability to explore a T-shaped maze improved. In the beginning, they followed random patterns. After only 17 days they were exploring like normal mice.
The improvements continued for two months after the drug therapy ended.
The drug controls the ability of neurons to make connections with each other, a process that is necessary to learning and memory.
People with Down syndrome or "trisomy 21" have an extra complete or partial copy of chromosome 21, whereas most people have two. It is evident at birth and is associated by facial and body structure alterations. Symptoms include impairment of physical and cognitive development, including heart problems.
This is a problem many parents face with their children. The cost associated with down syndrome is prohibitive at both the personal and community level. A drug that allows people to learn better and function independently in society will be a miracle in many lives..
Statistically, one in 800 children born in the world have Down syndrome. Down syndrome does not prejudice across ethnic or socioeconomic groups. However, babies born to older mothers have an increased risk of Down syndrome. The ratio increases from one in 1,000 in the mother’s twenties, to one in 11 when the mother reaches 49 years old.
Garner and his team claim that over-inhibition of neuronal excitation contributes to the intellectual disability that is commonly associated with Down syndrome.
They believe that GABAA could treat the disorder.
Applying this knowledge to humans is not simple. Large doses of this drug causes epileptic seizures. This is why The Food and Drug Administration withdrew approval for its use in the 1980s.
The research is positive, but people are warned to remember that many drugs which improve learning and cognitive functioning in mice have not worked as well in humans.
"Pharmacotherapy for cognitive impairment in a mouse model of Down syndrome."
Nature Neuroscience Published online: 25 February 2007
However, people who are struggling to create a life for those who suffer from Down Syndrome are not quick to turn their back on any possible treatment. Even if this drug can improve patients ability to learn how to live independently, slightly, it is worth extending the studies and learning more about the treatments available to patients.
By: Ethan Miller -