Jet lag recovery sped up in mice

Date: Aug-30-2013New research led by the University of Oxford in the UK suggests it may be possible to speed up recovery from jet lag by targeting a mechanism that prevents the body clock adjusting quickly to changes in patterns of light and
dark.

Working on mice, they found a protein called SIK1 acts as a buffer or brake to limit the effect of light on the body
clock. When they blocked the activity of the protein, the mice adjusted faster to changes in their light/dark
cycle.

One of the team leaders, Dr. Stuart Peirson from Oxford's Nuffield Laboratory of Ophthalmology, says they found a
mechanism that "actively prevents the body clock from re-adjusting," and explains it makes sense to have such a system
because it keeps the body clock stable:

"The clock needs to be sure that it is getting a reliable signal, and if the signal occurs at the same time over
several days it probably has biological relevance. But it is this same buffering mechanism that slows down our ability
to adjust to a new time zone and causes jet lag."

The study, which was funded by the Wellcome Trust and F. Hoffmann La Roche, was published online in the journal
Cell on August 29th.
Body clock synchronizes rhythm of life

Nearly all living things have an internal body clock that syncs their biology to a 24-hour cycle, ensuring
functions like sleeping and eating are correctly tuned to daily patterns of light and dark.

Researchers found a protein that limits the effect of light on the body, potentially speeding up recovery from jet lag.

When we travel to a different time zone, this "circadian clock" takes time to adjust to the shifted pattern of day
and night. This can take up to 1 day for every shifted hour, resulting in several days of fatigue and confusion.

Scientists have discovered that in mammals, the circadian clock is regulated by the brain's suprachiasmatic nuclei
(SCN), which ensures every cell of the body dances to the same biological rhythm.

The SCN in turn is regulated by a system linked to the eyes that senses light to determine time of day and to keep the
circadian clock tuned to local time.
Speeding up body clock adjustment

But until this latest study, it was not clear exactly how SCN uses light to tune the body clock and why it takes so
long for it to adjust when the pattern of light/dark shifts, such as when we jet to a new time zone.

The researchers decided to investigate this by looking at patterns of gene expression that affect the SCN in
mice.

They found about 100 genes were involved in responding to light and dark, causing a sequence of molecular patterns
that retuned the mice's circadian clocks.

They found that one molecule in particular, a protein called salt inducible kinase 1 (SIK1), acts like a buffer or
brake to limit the effects of light on the circadian clock. And when they blocked SIK1 in the mice, the animals adjusted more quickly to changes in their light/dark cycle.
Cure for jet lag still years away

The researchers point out these findings do not mean that a cure for jet lag is going to be easy to find.

A large body of evidence shows disruption to the body clock is linked to diseases like diabetes, cancer and heart
disease.

Researchers have found a disrupted body clock also
weakens immunity and can affect thinking and memory; it also features in schizophrenia and other mental
illnesses.

Professor Russell Foster, director of the Sleep and Circadian Neuroscience Institute at Oxford, who co-led the team
with Dr. Peirson, says:

"We're still several years away from a cure for jet-lag, but understanding the mechanisms that generate and regulate
our circadian clock gives us targets to develop drugs to help bring our bodies in tune with the solar cycle."

"Such drugs could potentially have broader therapeutic value for people with mental health issues," he adds.

In 2012, researchers in Australia reported a device resembling a pair of sunglasses that resets the body clock. The team said the
device, which emits a soft green light onto the eyes, can counter the effects of jet lag and keep shift workers more
alert.
Written by Catharine Paddock PhD

Copyright: Medical News Today

Not to be reproduced without permission of Medical News Today
Courtesy: Medical News Today Note: Any medical information available in this news section is not intended as a substitute for informed medical advice and you should not take any action before consulting with a health care professional.