Featured Research

from universities, journals, and other organizations

Light used to make the heart stumble

Date:
October 4, 2010
Source:
Bonn, Universitaet
Summary:
Scientists have altered cardiac muscle cells to make them controllable with light. They were thus able to use directed light to cause conditions such as arrhythmia in genetically modified mice. The method opens up completely new possibilities for researching the development of such arrhythmias.

Scientists at the University of Bonn have altered cardiac muscle cells to make them controllable with light. They were thus able to use directed light to cause conditions such as arrhythmia in genetically modified mice. The method opens up completely new possibilities for researching the development of such arrhythmias. The study will be published in the upcoming edition of Nature Methods.

Related Articles


Tobias Brügmann and his colleagues from the University of Bonn's Institute of Physiology I used a so-called "channelrhodopsin" for their experiments, which is a type of light sensor. At the same time, it can act as an ion channel in the cell membrane. When stimulated with blue light, this channel opens, and positive ions flow into the cell. This causes a change in the cell membrane's pressure, which stimulates cardiac muscle cells to contract.

"We have genetically modified mice to make them express channelrhodopsin in the heart muscle," explains Professor Dr. Bernd Fleischmann of the Institute for Physiology I. "That allowed us to change the electric potential of the mouse heart at will, enabling us to selectively produce conditions such as arrhythmia of the atrium or the ventricle."

These types of arrhythmia -- physicians also call them ventricular fibrillation -- are among the most common causes of death after a heart attack. They develop when large quantities of cardiac cells die and are replaced with connective tissue. "This scar tissue has a different electrical activity than the healthy heart muscle," says the leader of the study, Professor Dr. Philipp Sasse. "And that makes the heart stumble."

But why is that so? Normally, electric impulses spread across the heart from a natural pacemaker. This happens in a temporally and spatially tightly controlled manner, creating a closely coordinated contraction. However, if entire muscle areas decouple electrically, this mechanism no longer works: all of a sudden, certain parts of the heart pulse at their own rhythm. This causes the blood flow to come to a near-standstill.

The scientists from Bonn can now trigger this decoupling through photostimulation. They can target just a few cells at a time or direct larger areas of the heart, allowing them to find out, for instance, which areas of the hollow muscle are especially sensitive to electric disruptions.

But why not simply stimulate the heart muscle with electrodes in order to make the heart lose its rhythm? "That can be done as well," says Professor Sasse. " But this method has unwanted side effects: if the electric stimulation lasts longer than a few milliseconds, toxic gases are produced, and the pH value changes."

The consequences of a heart attack, which leads to permanent tissue damage, can of course only be studied in a very limited form when using short-term electric stimulation. Photostimulation is much more suitable: the cells will even withstand stimulations of several minutes at a time without problems.

Using channelrhodopsin in medical research is not fundamentally new, although so far it has mainly been used in neuroscience. For instance, scientists can use these light channels to direct the behavior of flies and mice -- with nothing but blue light.


Story Source:

The above story is based on materials provided by Bonn, Universitaet. Note: Materials may be edited for content and length.


Journal Reference:

  1. Tobias Bruegmann, Daniela Malan, Michael Hesse, Thomas Beiert, Christopher J Fuegemann, Bernd K Fleischmann, Philipp Sasse. Optogenetic control of heart muscle in vitro and in vivo. Nature Methods, 2010; DOI: 10.1038/nmeth.1512

Cite This Page:

Bonn, Universitaet. "Light used to make the heart stumble." ScienceDaily. ScienceDaily, 4 October 2010. <www.sciencedaily.com/releases/2010/10/101003205740.htm>.
Bonn, Universitaet. (2010, October 4). Light used to make the heart stumble. ScienceDaily. Retrieved November 28, 2014 from www.sciencedaily.com/releases/2010/10/101003205740.htm
Bonn, Universitaet. "Light used to make the heart stumble." ScienceDaily. www.sciencedaily.com/releases/2010/10/101003205740.htm (accessed November 28, 2014).

Share This


More From ScienceDaily



More Health & Medicine News

Friday, November 28, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Rural India's Low-Cost Sanitary Pad Revolution

Rural India's Low-Cost Sanitary Pad Revolution

AFP (Nov. 28, 2014) — One man hopes his invention -– a machine that produces cheap sanitary pads –- will help empower Indian women. Duration: 01:51 Video provided by AFP
Powered by NewsLook.com
Research on Bats Could Help Develop Drugs Against Ebola

Research on Bats Could Help Develop Drugs Against Ebola

AFP (Nov. 28, 2014) — In Africa's only biosafety level 4 laboratory, scientists have been carrying out experiments on bats to understand how virus like Ebola are being transmitted, and how some of them resist to it. Duration: 01:18 Video provided by AFP
Powered by NewsLook.com
WHO Says Male Ebola Survivors Should Abstain From Sex

WHO Says Male Ebola Survivors Should Abstain From Sex

Newsy (Nov. 28, 2014) — WHO cites four studies that say Ebola can still be detected in semen up to 82 days after the onset of symptoms. Video provided by Newsy
Powered by NewsLook.com
Ebola Leaves Orphans Alone in Sierra Leone

Ebola Leaves Orphans Alone in Sierra Leone

AFP (Nov. 27, 2014) — The Ebola epidemic sweeping Sierra Leone is having a profound effect on the country's children, many of whom have been left without any family members to support them. Duration: 01:02 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