Gene mutations in mice mimic human-like sleep disorder, researchers find

May 20, 2008

DALLAS – May 20, 2008 – Mutations in two genes that control electrical excitability in a portion of the brain involved in sleep create a human-like insomnia disorder in mice, UT Southwestern Medical Center researchers have found. The findings may help scientists better understand the disorder and provide an animal model for developing treatments.

“This is one of the most dramatic sleep-disturbance mutations,” said Dr. Rolf Joho, associate professor of neuroscience and senior author of the paper, which appears online today and in the May 21 issue of The Journal of Neuroscience. “The mice sleep half as much as normal mice.”

The mutant mice appeared to have a condition similar to a human disorder called sleep maintenance insomnia, in which sufferers can get to sleep, but don’t remain at rest for long.

“We’re trying to look at where in the brain this originates,” Dr. Joho said. “The same mechanism could be involved in many neurophysiological disorders.”

The researchers focused on two genes that encode molecules known as ion channels. An ion channel is a pore that spans a cell’s membrane, opening and closing to allow charged atoms, or ions, to cross the membrane. The coordinated opening and closing of various ion channels allows nerve cells to carry electrical signals.

In the current study, the researchers examined two channels that allow potassium ions to cross the cell membrane. The researchers genetically engineered mice to have defects in the ion channels Kv3.1 and Kv3.3, which normally open and close much faster than other potassium channels.

These channels are common in a portion of the brain called the thalamic reticular nucleus, which is thought to act as a “pacemaker” during sleep, controlling slow-wave sleep – the deep, restful sleep that occurs without dreams.

The mutant mice slept only 50 percent to 60 percent as much as normal mice. Measurements of their brain waves showed that they entered slow-wave sleep, but only for short periods before waking again.

The mice did not readily get restful sleep even after sleep deprivation, the researchers found.

In future studies, the researchers hope to focus on the Kv3.1 mutation alone, which they believe, based on previous studies might be the primary factor in the sleep disturbances, while Kv3.3 mutations might affect muscle coordination.

The researchers also plan to investigate ways to restore function of Kv3.1 with potential drugs. So far, there are no medications that affect this ion channel.

Source: UT Southwestern Medical Center

Explore further: Stem cells faulty in Duchenne muscular dystrophy

add to favorites email to friend print save as pdf

Related Stories

Researchers unwind the mysteries of the cellular clock

Nov 20, 2014

Human existence is basically circadian. Most of us wake in the morning, sleep in the evening, and eat in between. Body temperature, metabolism, and hormone levels all fluctuate throughout the day, and it ...

Reading a biological clock in the dark

Oct 21, 2014

Our species' waking and sleeping cycles – shaped in millions of years of evolution – have been turned upside down within a single century with the advent of electric lighting and airplanes. As a result, ...

Engineering light-controlled proteins

Jul 03, 2014

(Phys.org) —A University of Wyoming professor has engineered proteins that can be activated by near-infrared light as a way to control biological activities in deep tissues of small mammals.

Recommended for you

Stem cells faulty in Duchenne muscular dystrophy

2 hours ago

Like human patients, mice with a form of Duchenne muscular dystrophy undergo progressive muscle degeneration and accumulate connective tissue as they age. Now, researchers at the Stanford University School of Medicine have ...

Here's how the prion protein protects us

7 hours ago

The cellular prion protein (PrPC) has the ability to protect the brain's neurons. Although scientists have known about this protective physiological function for some time, they were lacking detailed knowledge ...

Regulation of maternal miRNAs in early embryos revealed

8 hours ago

The Center for RNA Research at the Institute for Basic Science (IBS) has succeeded in revealing, for the first time, the mechanism of how miRNAs, which control gene expression, are regulated in the early embryonic stage.

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.