Drugs May Save Memory of the Sleep-Deprived

Memory fuzzy after missing out on sleep ? Researchers may be
one step closer to figuring out what to do about it.

Sleep deprivation makes it harder for the brain to memorize newly learned
information, and scientists may have found a way around that problem.

Writing in Nature, University of Pennsylvania graduate student
Christopher G. Vecsey, professor Ted Abel, PhD, and colleagues identify a
chemical chain reaction linked to sleep deprivation -- and a possible
solution.

The researchers used electrical shocks to train lab mice not to move in
certain cages, and then deprived some of the mice of sleep for five hours.
Those sleep-deprived mice were worse at remembering not to move around in those
cages than mice that had been allowed to sleep.

When deprived of sleep, the mice made more of an enzyme called
phosphodiesterase 4 (PDE4). In turn, the surplus of PDE4 caused a shortfall of
a compound called cAMP, which is involved in forming new memories in a brain
area called the hippocampus.

The researchers ran the tests on more mice. And this time, they injected
some of the mice with rolipram, an experimental drug that blocks PDE4. For
comparison, other mice got placebo shots.

The mice got those shots right after being trained not to move in certain
cages, but before sleep deprivation. Sleep-deprived mice that had gotten the
rolipram shot aced the memory test; they remembered not to scurry around the
cages where they were likely to get shocked.

The researchers aren't recommending rolipram for sleep-deprived people.

But they say their study shows that "it may be possible" to make drugs that
target PDE4, and that such drugs "may prove useful in the treatment of the
cognitive effects of sleep deprivation."

By Miranda Hitti
Reviewed by Louise Chang
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