Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


When the Villain Becomes your Friend: The Strange Tale of Muscle Lactate

In a paper published this week in The Journal of Physiology, Frank de Paoli and colleagues, working at the University of Aarhus in Denmark, add to the growing literature leading to a more complete understanding of the physiological role of lactic acid production in muscle.

In the late 19th century, fermentation chemists realized that juice left to ferment without adequate oxygen resulted in acid products. Then, in the early 20th century, when physiologists stimulated isolated frog muscles to contract until exhaustion, they found that the tissues had accumulated high amounts of lactic acid. Since then, the idea that lactic acid accumulation causes muscle fatigue has persisted. But did early scientists fail to address the various issues adequately and interpret the results appropriately? Did they fail to ask the essential question “Why does nature make lactic acid?”, and did they in effect put one and one together and make them a minus?

De Paoli and colleagues looked at the effects of lactic acid and adrenaline on the processes that signal contractions in skeletal muscles. Using rat muscles, the study examined the combined effect of potassium ions, lactic acid and adrenaline on the electrical signalling system that serves to forward the activating signals from the brain to the muscle fibres where contraction takes place. They showed that in combination, lactic acid and adrenalin serve to help working muscles ward off the effects of potassium ions which leak from the inside to the outside of working muscle cells and negatively effect the signaling process by which muscles contract. In this, the latest of a series of reports from the Aarhus group, in combination with reports from other scientists in Scandinavia, the UK, US and Canada, long-standing ideas about the role of lactic acid in muscle are being overturned.

So, why do muscles contract? Usually, muscles contract because the central and peripheral nervous system signals them to do so. Why do the muscles make lactic acid? Lactic acid is the result of the glycolytic energy production system. It is an energy source to be used in muscle cells of origin, or adjacent fibres (cells), or fibres in the heart and cells in the brain. Lactic acid is also the material that the liver prefers to make glucose (sugar) for the blood when exercise is prolonged. Lactic acid production in muscle is stimulated in part by circulating adrenalin. Now, from de Paoli and colleagues we learn that adrenalin and lactic acid also help protect against the electrolyte imbalance across muscle membranes brought on by the loss of potassium.

... more about:
»Adrenalin »Lactic acid »acid »lactic »potassium

Why does potassium have such a negative effect? In the study, when potassium ions outside the muscle fibres were increased to levels seen during intense exercise, the ability of the signalling system to forward electrical signals was profoundly reduced and the muscle became paralysed. If, however, lactic acid and adrenaline were added in combination, the function of the signalling system was largely recovered and the contractile response of the muscles restored. It was further shown that the positive effect of lactic acid was specifically related to an acidification of the interior of the muscle cells, which is one of the hallmarks of intense exercise.

The muscle lactic acid story, however, is still incomplete. It may even be found that lactate production is adaptive because its presence signals the activation of genes responsible for controlling muscle function. So, it seems that there is wisdom in the way that the body functions, a retrospective realisation that seems obvious, and which for lactic acid is supported by a century of strides even after a few false steps.

Melanie Thomson | alfa
Further information:

Further reports about: Adrenalin Lactic acid acid lactic potassium

More articles from Life Sciences:

nachricht Gene therapy shows promise for treating Niemann-Pick disease type C1
27.10.2016 | NIH/National Human Genome Research Institute

nachricht 'Neighbor maps' reveal the genome's 3-D shape
27.10.2016 | International School of Advanced Studies (SISSA)

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Etching Microstructures with Lasers

Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.

This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...

Im Focus: Light-driven atomic rotations excite magnetic waves

Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion

Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

How nanoscience will improve our health and lives in the coming years

27.10.2016 | Materials Sciences

OU-led team discovers rare, newborn tri-star system using ALMA

27.10.2016 | Physics and Astronomy

'Neighbor maps' reveal the genome's 3-D shape

27.10.2016 | Life Sciences

More VideoLinks >>>