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 April 21, 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 April 21, 2014).

Share This



More Health & Medicine News

Monday, April 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Nine-Month-Old Baby Can't Open His Mouth

Nine-Month-Old Baby Can't Open His Mouth

Newsy (Apr. 19, 2014) Nine-month-old Wyatt Scott was born with a rare disorder called congenital trismus, which prevents him from opening his mouth. Video provided by Newsy
Powered by NewsLook.com
'Holy Grail' Of Weight Loss? New Find Could Be It

'Holy Grail' Of Weight Loss? New Find Could Be It

Newsy (Apr. 18, 2014) In a potential breakthrough for future obesity treatments, scientists have used MRI scans to pinpoint brown fat in a living adult for the first time. Video provided by Newsy
Powered by NewsLook.com
Little Progress Made In Fighting Food Poisoning, CDC Says

Little Progress Made In Fighting Food Poisoning, CDC Says

Newsy (Apr. 18, 2014) A new report shows rates of two foodborne infections increased in the U.S. in recent years, while salmonella actually dropped 9 percent. Video provided by Newsy
Powered by NewsLook.com
Scientists Create Stem Cells From Adult Skin Cells

Scientists Create Stem Cells From Adult Skin Cells

Newsy (Apr. 17, 2014) The breakthrough could mean a cure for some serious diseases and even the possibility of human cloning, but it's all still a way off. Video provided by Newsy
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:
from the past week

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