New Treatment for Jet Lag Could Fly Our Way

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Love to fly but hate the jet lag? Have to fly and hate the jet lag even more? Scientists at the Max Planck Institute for Biophysical Chemistry have discovered that, at least in mice a new treatment for jet lag. According to their research jet lag can be significantly improved by altering the body’s internal clock.

Everyone has an internal body clock that follows a certain circadian rhythm of day and night. When that rhythm is disrupted by crossing over multiple time zones, many of the body’s functions are triggered into action at the wrong time. The result for a few days after the flight is crippling exhaustion during the day and an inability to sleep at night. Within a few days, however, the body adjusts to the new external time.

Internal Clocks and Clock Genes
The body’s internal body clock consists of a network of molecular clocks and individual genes distributed in the various organs, and they coordinate different processes such as heart beat, sleep, temperature, hormone balance, and behavior. All these individual clocks are controlled by a master pacemaker that synchronizes all of the individual clocks with the external world.

Scientists at the Max Planck Institute discovered how these individual clock genes and the different internal clocks synchronize with the new external time in jet lag. They found that “the internal clocks and the ‘clock’ genes adapt to the altered external influences at varying speeds,” notes Gregor Eichele, director of the Institute’s Genes and Behaviour Department. Thus when people suffer from jet lag, it appears that their entire clock process fails to “tick at the right rhythm.” This throws their physiological processes into disarray and the symptoms of jet lag result.

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Mice and Jet Lag
The scientists discovered that if they turned off the adrenal clock in mice, they were able to much more quickly adapt to their new external time: in their case, return to their laps on the wheel. Because the adrenal gland produces essential hormones such as adrenaline, noradrenaline, and cortisol (corticosterone in mice), turning off the adrenal clock completely is not advisable.

However, the scientists found that in mice, the time-dependent release of corticosterone was the factor that allowed the rodents to quickly adapt to their new external time. When the mice were give metyrapone at the right time in the cycle, “they adapted faster to the disturbed circadian rhythm.”

Metyrapone is a drug used in the diagnosis of certain problems associated with the adrenal glands. These glands produce cortisol, which helps the body respond to stress and illness. The results of a metyrapone test tell physicians if the adrenal glands are producing the right amount of cortisol when the body is under stress.

The findings of these scientists could lead to a new approach to the treatment of jet lag. Since metyrapone already has approval for other purposes, it remains to be shown in clinical studies and tests in sleep labs whether it can provide relief from jet lag in humans. For now, mice that cross over multiple time zones have a way to get relief from jet lag.

SOURCES:
Kiessling S et al. Journal of Clinical Investigation 2010 Jun 23
Mayo Clinic

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