Study Examines How Muscles Are Paralyzed While We Sleep

Editor’s ChoiceMain Category: Sleep / Sleep Disorders / InsomniaArticle Date: 24 Jul 2012 – 8:00 PDT

Current ratings for:Study Examines How Muscles Are Paralyzed While We Sleep

A new study, published in the July 18 edition of The Journal of Neuroscience, has discovered a way to help researchers gain a better understanding and to offer better treatment for sleep disorders, such as REM sleep behavior disorder, narcolepsy and tooth grinding. The study discovered that two powerful brain chemical systems work jointly to paralyze skeletal muscles during rapid eye movement (REM) sleep. 

During REM sleep, i.e. the sleeping phase in which most dreams we recall occur, muscles that grant eye movement and breathing continue to move, whilst the majority of other muscles are prevented from moving, which may be due to prevent injury. 

Toronto University’s neuroscientists Patricia L. Brooks and John H. Peever, PhD, discovered in various rat experiments that the neurotransmitters gamma-aminobutyric acid (GABA) and glycine caused REM sleep paralysis by “switching off” special brain cells that control muscle activity. The discovery revokes previous beliefs of glycine being the sole inhibitor of these motor neurons. 

Dennis J. McGinty, PhD, a behavioral neuroscientist and sleep researcher from the University of California in L.A. commented:

“The study’s findings are relevant to anyone who has ever watched a sleeping pet twitch, gotten kicked by a bed partner, or has known someone with the sleep disorder narcolepsy. By identifying the neurotransmitters and receptors involved in sleep-related paralysis, this study points us to possible molecular targets for developing treatments for sleep-related motor disorders, which can often be debilitating.” McGinty was not involved in the study.

The researchers measured electrical activity in the facial muscles that are responsible for chewing of sleeping rats, which are controlled by trigeminal motor neurons (a type of brain cell) that transmits the brain’s message to activate movement in these muscles. Earlier studies indicated that REM sleep paralysis is caused by ionotropic GABAA/glycine receptors, i.e. neurotransmitter receptors in the motor neurons, yet when the team inhibited these receptors, they discovered that REM sleep paralysis still occurred. 

To prevent REM sleep paralysis, the team had to inhibit both the GABAA/glycine ionotropic receptors and a different receptor system, called metabotropic GABAB receptors. This means by slicing off the motor cells from all sources of GABA and glycine no paralysis occured, which enabled high levels of muscle activity in the animals when their muscles should have been inactive, which indicates that instead of working separately, the two neurotransmitters must both be present together to maintain motor control during sleep. 

The discovery could be particularly beneficial for people suffering from REM sleep disorder, a condition, which causes people to act out their dreams and which can lead to serious injuries to the patients themselves as well as to others. REM sleep disorder is also frequently an early indicator of neurodegenerative diseases like Parkinson’s disease. 

“Understanding the precise mechanism behind these chemicals’ role in REM sleep disorder is particularly important because about 80 percent of people who have it eventually develop a neurodegenerative disease, such as Parkinson’s disease. REM sleep behavior disorder could be an early marker of these diseases, and curing it may help prevent or even stop their development.”

Written by Grace Rattue Copyright: Medical News TodayNot to be reproduced without permission of Medical News Today

Visit our sleep / sleep disorders / insomnia section for the latest news on this subject. Please use one of the following formats to cite this article in your essay, paper or report:

Please note: If no author information is provided, the source is cited instead.

‘Study Examines How Muscles Are Paralyzed While We Sleep’

Please note that we publish your name, but we do not publish your email address. It is only used to let you know when your message is published. We do not use it for any other purpose. Please see our privacy policy for more information.

If you write about specific medications or operations, please do not name health care professionals by name.

All opinions are moderated before being included (to stop spam)

For any corrections of factual information, or to contact the editors please use our feedback form.Please send any medical news or health news press releases to:

Note: Any medical information published on this website is not intended as a substitute for informed medical advice and you should not take any action before consulting with a health care professional. For more information, please read our terms and conditions.

Related News:

• Astellas, Ambit announce results from quizartinib Phase 2 study on acute myeloid leukemia
• Impact of Medicaid expansion would vary by state, according to study
• Fish, But Not Fish Oil Supplements, May Shield Against Stroke
• Antidepressant eases radiation-related mouth pain in head, neck cancer
• Study: More Birth Defects with In Vitro
• Antidepressants and Stroke
• Vaccine Safety
• Children and CT Concerns
• Study: Hint of Benefit for Alzheimer’s Drug
• Study provides direct evidence for persistent activity in medial entorhinal cortex layer neurons

Details :
Submited at Tuesday, July 24th, 2012 at 4:15 pm on Uncategorized by robert
Comment RSS 2.0 - leave a comment - trackback