Drug induced increases in levels of the brain neurotransmitter norepinephrine can overcome memory problems and improve cognitive development in mice with genetically-engineered Down syndrome, according to scientists at Stanford.
Ahmad Salehi and colleagues postulate that similar interventions, if applied early enough in children with Down syndrome, might improve their cognitive development as well.
Their write-up appears in Science Translational Medicine.
In the article, Salehi’s group showed that drugs which enhanced norepinephrine signaling in the brains of the genetically engineered mice rapidly restored cognitive function, enabling them to handle simple challenges like building a nest.
The treated mice could make nests as well as normal mice. Untreated mice were unable to do so. The beneficial effects became apparent just hours after treatment was initiated. They waned quickly following discontinuation of the drugs.
Salehi’s genetically-engineered mice exhibited early degeneration of the locus ceruleus, a part of the brain that supplies norepinephrine to the hippocampus, which is involved with memory formation. The same findings have been demonstrated in humans with Down syndrome.
Several drugs that have been approved by the FDA for treatment of depression and ADHD have the same effects on brain norepinephrine levels as those used in the Stanford study. Because these drugs have proven to be safe in humans (though not infants), Salehi told BurrillReport he hoped his results would quickly lead to human trials.
Previous efforts to modify the course of Down syndrome with drugs have focused on acetylcholine, a separate neurotransmitter that also acts on the hippocampus.