Featured Research

from universities, journals, and other organizations

New insights into the mechanics of muscle fatigue

Date:
January 17, 2013
Source:
Rockefeller University Press
Summary:
A new study examines the consequences of muscle activity with surprising results, indicating that the extracellular accumulation of potassium that occurs in working muscles is considerably higher than previously thought.

A study in The Journal of General Physiology examines the consequences of muscle activity with surprising results, indicating that the extracellular accumulation of potassium that occurs in working muscles is considerably higher than previously thought.

Muscle excitation involves the influx of sodium ions and efflux of potassium ions. Although the fraction of ions that cross the muscle membrane with each contraction is minute, repeated activity can lead to substantial changes in the intracellular and extracellular concentrations of sodium and potassium ions. The extent of these changes, however, has been unclear. Now, Torben Clausen from Aarhus University in Denmark provides quantitative analyses of the changes in intracellular and extracellular ion concentration resulting from stimulation of a leg muscle in rats, providing insight into how they vary with muscle activity.

Clausen measured the changes in concentration of sodium, potassium, and chloride ions in working rat extensor digitorum longus (ESL) muscles. Remarkably, when their muscles were stimulated to fire at a rate of 5 Hz (comparable to that in the legs of a person riding a bicycle) for five minutes, sufficient intracellular potassium was lost to lead to an extracellular concentration that would interfere with further excitation. These results suggest that accumulation of extracellular potassium is a much larger contributor to muscle fatigue than previously thought, which may be of particular importance in such conditions as hyperkalemic periodic paralysis and other channelopathies that affect skeletal muscle.

These changes in ion distribution are opposed through the action of the "Na+/K+ pump" -- which expends energy to move sodium out of the cell and potassium into it -- and will therefore be even more pronounced under disease- and injury-related conditions associated with decreased pump activity.


Story Source:

The above story is based on materials provided by Rockefeller University Press. Note: Materials may be edited for content and length.


Journal Reference:

  1. T. Clausen. Excitation-induced exchange of Na , K , and Cl- in rat EDL muscle in vitro and in vivo: Physiology and pathophysiology. The Journal of General Physiology, 2013; DOI: 10.1085/jgp.201210892

Cite This Page:

Rockefeller University Press. "New insights into the mechanics of muscle fatigue." ScienceDaily. ScienceDaily, 17 January 2013. <www.sciencedaily.com/releases/2013/01/130117111844.htm>.
Rockefeller University Press. (2013, January 17). New insights into the mechanics of muscle fatigue. ScienceDaily. Retrieved October 20, 2014 from www.sciencedaily.com/releases/2013/01/130117111844.htm
Rockefeller University Press. "New insights into the mechanics of muscle fatigue." ScienceDaily. www.sciencedaily.com/releases/2013/01/130117111844.htm (accessed October 20, 2014).

Share This



More Health & Medicine News

Monday, October 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Microneedle Patch Promises Painless Pricks

Microneedle Patch Promises Painless Pricks

Reuters - Innovations Video Online (Oct. 18, 2014) Researchers at The National University of Singapore have invented a new microneedle patch that could offer a faster and less painful delivery of drugs such as insulin and painkillers. Video provided by Reuters
Powered by NewsLook.com
Raw: Nurse Nina Pham Arrives in Maryland

Raw: Nurse Nina Pham Arrives in Maryland

AP (Oct. 17, 2014) The first nurse to be diagnosed with Ebola at a Dallas hospital walked down the stairs of an executive jet into an ambulance at an airport in Frederick, Maryland, on Thursday. Pham will be treated at the National Institutes of Health. (Oct. 16) Video provided by AP
Powered by NewsLook.com
Raw: Cruise Ship Returns to US Over Ebola Fears

Raw: Cruise Ship Returns to US Over Ebola Fears

AP (Oct. 17, 2014) A Caribbean cruise ship carrying a Dallas health care worker who is being monitored for signs of the Ebola virus is heading back to Texas, US, after being refused permission to dock in Cozumel, Mexico. (Oct. 17) Video provided by AP
Powered by NewsLook.com
Spanish Govt: Four Suspected Ebola Cases in Spain Test Negative

Spanish Govt: Four Suspected Ebola Cases in Spain Test Negative

AFP (Oct. 17, 2014) All four suspected Ebola cases admitted to hospitals in Spain on Thursday have tested negative for the deadly virus in a first round of tests, the government said Friday. Duration: 00:55 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins