According to US researchers, increasing levels of a message-carrying chemical in the brain, helps reduce memory deficits in Down syndrome responsible for hindering learning and making it difficult for normal development of the brain.

For the study, drugs were injected into mice with a rodent version of Down syndrome to increase neuro-transmitter norepinephrine levels, which helps nerve cells communicate, showing marked improvements in their thinking ability.

These finding will help find new ways of improving deficits seen in Down syndrome, affecting 5,000-newborns in the USA each year.

Dr Ahmad Salehi, whose study has been published in the journal Science Translational Medicine says, by intervening early, it is possible to help children with Down syndrome to collect and modulate information, leading to improved cognitive functions.

An individual is said to have Down syndrome when he carries an extra copy of chromosome 21. While, Down syndrome children are not developmentally delayed at birth, because of memory deficits linked with the disorder hindering normal brain development.

Salehi and his team of researchers simulated the same in mice with an extra copy of chromosome 16, which resulted in mental disabilities similar to those witnessed in people with Down syndrome.

Researchers found mice with Down syndrome similar dysfunction had lower norepinephrine levels in the brain compared to normal mice, a problem that occurred in a part of the brain known as the locus coeruleus.

A break-down in this part of the brain did not elicit normal behaviour in the mice, such as, engineered mice when placed in a strange cage failed to build nests, as something normal mice did.

However, when given drugs for boosting their norepinephrine levels, within a few hours of taking the drugs, the mice built nests on par with those of normal mice.

Salehi was completely surprised at how fast the drug worked, though it was noticed the effects did not last long.

Some depression and attention deficit hyperactivity disorder drugs already on the market target norepinephrine. And, the norepinephrine precursor used in the Down Syndrome study is currently being tested for treating fibromyalgia in humans, a chronic condition characterized by fatigue and widespread pain.