Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

UBC researchers illuminate link between sodium, calcium and heartbeat using Canadian Light Source

14.02.2012
That flutter in your heart may have more to do with the movement of sodium ions than the glance of a certain someone across a crowded room.

Using the Canadian Light Source synchrotron, researchers from the University of British Columbia have revealed, for the first time, one of the molecular mechanisms that regulates the beating of heart cells by controlling the movement of sodium in out of the cells – and what calcium has to do with it.

The findings, published February 14 in the Proceedings of the National Academy of Sciences, sheds new light on this crucial physiological process while revealing the root cause and possible treatment targets of two potentially life-threatening cardiac arrhythmia conditions.

The contraction and relaxation of heart muscle cells depend on minute but finely regulated electrical impulses that are created when charged atoms – or ions – of metals such as sodium, potassium and calcium pass through complex molecular channels inside and between cells. Irregular heartbeats, referred to medically as arrhythmias, can happen when these channels leak or otherwise malfunction. Professors Filip van Petegem and Christopher Ahern, members of UBC's Cardiovascular Research Group, used the CLS to determine the molecular structure of a part of the channel that controls the flow of sodium to cells in the heart, as well as in other electrically-excitable cells such as in the nervous system.

"The heart is an electrical organ that depends on precise electrical signals to contract [and pump blood]" explains van Petegem. "It is crucial for heart rate that the signalling, controlled by the movement of sodium, be exact. So the entry of sodium into the cell is tightly regulated."

The sodium channel that passes through the outer membrane of heart cells is actually a huge, intertwined four-part molecule. The teams of Van Petegem and Ahern chose a section of the molecule that appeared to regulate the closing of the channel by forming a plug, thus stopping sodium from getting through.

The researchers were surprised to discover that a protein called calmodulin binds to the sodium channel, keeping it open by preventing the plug from forming. Calcium ions, in turn, regulate the connection between the protein and the channel: calcium ions cause the protein to hook up to the channel, keeping it open and letting sodium through.

Problems occur with the system when genetic mutations change the shape of the channel at the site where the protein binds, affecting how well the channel can open and close. The result – the flow of sodium into the muscle cells is disrupted and the heart does not beat regularly.

The scientists have been able to identify mutations in the site that lead to two different kinds of heart arrhythmia: Brugada Syndrome and Long Q-T type 3, so-called from the tell-tale trace doctors see on the ECG of patients suffering from the problem. Brugada syndrome is considered to be caused by not enough sodium getting into cells, while long Q-T is the result of too much sodium.

The results of the study could pave the way for the development of new drugs that can shore up how the calmodulin protein binds to the sodium channel, effectively treating both conditions as well as other arrhythmias.

"It's really a very elegant mechanism," notes van Petegem. "Many channels are regulated by calmodulin but not in such a simple way."

About the Canadian Light Source: The Canadian Light Source is Canada's national centre for synchrotron research and is a global leader and a recognized centre of excellence in synchrotron science and its applications. Located on the University of Saskatchewan campus in Saskatoon, the CLS has hosted over 4,600 user visits from academic institutions, government, and industry, and delivered over 15,000 experimental shifts to users from across Canada and 18 countries since 2005. CLS operations are funded by Western Economic Diversification Canada, Natural Sciences and Engineering Research Council, National Research Council of Canada, Canadian Institutes of Health Research, the Government of Saskatchewan and the University of Saskatchewan.

Matthew Dalzell | EurekAlert!
Further information:
http://www.lightsource.ca
http://www.lightsource.ca/media/quickfacts.php

More articles from Medical Engineering:

nachricht New imaging modality targets cholesterol in arterial plaque
14.06.2019 | SPIE--International Society for Optics and Photonics

nachricht Piedmont Atlanta first in Georgia to offer new minimally invasive treatment for emphysema
24.05.2019 | Pulmonx

All articles from Medical Engineering >>>

The most recent press releases about innovation >>>

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

Im Focus: MPSD team discovers light-induced ferroelectricity in strontium titanate

Light can be used not only to measure materials’ properties, but also to change them. Especially interesting are those cases in which the function of a material can be modified, such as its ability to conduct electricity or to store information in its magnetic state. A team led by Andrea Cavalleri from the Max Planck Institute for the Structure and Dynamics of Matter in Hamburg used terahertz frequency light pulses to transform a non-ferroelectric material into a ferroelectric one.

Ferroelectricity is a state in which the constituent lattice “looks” in one specific direction, forming a macroscopic electrical polarisation. The ability to...

Im Focus: Determining the Earth’s gravity field more accurately than ever before

Researchers at TU Graz calculate the most accurate gravity field determination of the Earth using 1.16 billion satellite measurements. This yields valuable knowledge for climate research.

The Earth’s gravity fluctuates from place to place. Geodesists use this phenomenon to observe geodynamic and climatological processes. Using...

Im Focus: Tube anemone has the largest animal mitochondrial genome ever sequenced

Discovery by Brazilian and US researchers could change the classification of two species, which appear more akin to jellyfish than was thought.

The tube anemone Isarachnanthus nocturnus is only 15 cm long but has the largest mitochondrial genome of any animal sequenced to date, with 80,923 base pairs....

Im Focus: Tiny light box opens new doors into the nanoworld

Researchers at Chalmers University of Technology, Sweden, have discovered a completely new way of capturing, amplifying and linking light to matter at the nanolevel. Using a tiny box, built from stacked atomically thin material, they have succeeded in creating a type of feedback loop in which light and matter become one. The discovery, which was recently published in Nature Nanotechnology, opens up new possibilities in the world of nanophotonics.

Photonics is concerned with various means of using light. Fibre-optic communication is an example of photonics, as is the technology behind photodetectors and...

Im Focus: Cost-effective and individualized advanced electronic packaging in small batches now available

Fraunhofer IZM is joining the EUROPRACTICE IC Service platform. Together, the partners are making fan-out wafer level packaging (FOWLP) for electronic devices available and affordable even in small batches – and thus of interest to research institutes, universities, and SMEs. Costs can be significantly reduced by up to ten customers implementing individual fan-out wafer level packaging for their ICs or other components on a multi-project wafer. The target group includes any organization that does not produce in large quantities, but requires prototypes.

Research always means trying things out and daring to do new things. Research institutes, universities, and SMEs do not produce in large batches, but rather...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

SEMANTiCS 2019 brings together industry leaders and data scientists in Karlsruhe

29.04.2019 | Event News

Revered mathematicians and computer scientists converge with 200 young researchers in Heidelberg!

17.04.2019 | Event News

First dust conference in the Central Asian part of the earth’s dust belt

15.04.2019 | Event News

 
Latest News

Concert of magnetic moments

14.06.2019 | Information Technology

Materials informatics reveals new class of super-hard alloys

14.06.2019 | Materials Sciences

New imaging modality targets cholesterol in arterial plaque

14.06.2019 | Medical Engineering

VideoLinks
Science & Research
Overview of more VideoLinks >>>