Navigation Links
Chloride channels render nerve cells more excitable
Date:4/21/2010

Nerve cells communicate with each other by means of electrical impulses. To create such an impulse, the cells exchange charged ions with their environment. However, the role played by the ever-present chloride channels remained obscure, although some theories predicted a relation between the chloride channel ClC-2 and epilepsy. Scientists at the Max Planck Institute of Neurobiology in Martinsried were now able to confirm a number of assumptions about the ClC-2 channel and could at last explain why the anticipated epileptic seizures do not occur when nerve cells lack the ClC-2 channels in mice. The results also provide a completely new understanding of how nerve cells may actively influence the exchange of information. (The Journal of Neuroscience online publication 01 April 2010)

The cell membranes of nerve cells, like those of all other cell types in the body, are perforated by so-called chloride channels. These permit the exchange of negatively charged chloride ions between the cell and its environment. Yet scientists could so far only speculate about the purpose of this exchange. According to one very prevalent theory, the excitability of nerve cells decreases when they lose chloride ions through these channels. Or, to put it the other way round, the lack of chloride channels would cause nerve cells to become overexcited. This in turn should lead to an increased rate of epileptic seizures. However, mice whose nerve cells lack chloride channels due to a genetic mutation were found no more susceptible to epilepsy than healthy animals. And so the function of the ClC-2 and of other chloride channels remained obscure.

Scientists at the Max Planck Institute of Neurobiology have now tracked down a number of the ClC-2 channel's functions. This constitutes the first tangible proof of the circumstances under which chloride ions can escape from nerve cells through the ClC-2 channels. In the case that nerve cells were lacking the ClC-2 channels due to a mutation in the channel's gene, the concentration of chloride inside the cells did indeed increase considerably.

The Max Planck scientists were also the first to successfully prove the third hypothesis that the nerve cells of mice with a genetic ClC-2 deficiency were much easier to excite than nerve cells in a healthy brain. Earlier assumptions therefore turned out to be correct. Then why did animals lacking the ClC-2 channels show no sign of epilepsy?

The answer to this question was not only plausible, but also straightforward. In addition to having cells that transmit information to their neighbouring cells, the nervous system contains a second group of nerve cells. These cells inhibit the exchange of information between its neighbours. In animals with a ClC-2 genetic defect, these inhibitory nerve cells also forfeit their chloride channels, and therefore become more excitable. Thus, excitatory and inhibitory cells become more excitable. "Although the whole system becomes more sensitive, at the end of the day the balance between the cells is maintained", explains Valentin Stein, leader of the study. And so the anticipated connection between genetic defect and epilepsy is not expressed. However, the lack of ClC-2 channels throws the nervous system into an unnaturally excited state. The scientists therefore speculate that although a defective ClC-2 gene does not cause epilepsy in itself, it may increase the risk of contracting epilepsy if other factors are present.

"We reckon, however, that we have come across something even more exciting", says Valentin Stein . The neurobiologist is referring to the discovery that nerve cells can theoretically use the ClC-2 channels to influence their own excitability. "If a nerve cell can control its own excitability by opening or closing its ClC-2 channels, then it could basically have a say in whether or not it transmits information to its neighbour." This possibility adds a whole new dimension to brain research. When and how nerve cells transmit information is one of the most fundamental functions of the brain and forms the basis of our ability to think. And so it comes as no surprise that the scientists can hardly wait to get on with the next stage of their investigations into this discovery.


'/>"/>

Contact: Valentin Stein
vstein@neuro.mpg.de
Max-Planck-Gesellschaft
Source:Eurekalert  

Related biology news :

1. Chloride increases response to pheromones and odors in mouse sensory neurons
2. Chloride found at levels that can harm aquatic life in urban streams of the Northern US
3. A lab-on-a-chip with moveable channels
4. MDC researchers develop new tool to investigate ion channels
5. Nervy research: Researchers take initial look at ion channels in a model system
6. Researcher says microchannels could advance tissue engineering methods
7. International collaboration by scientists culminates in novel ion channels database
8. New research helps explain how connexin hemichannels are kept closed
9. Journal of General Physiology explores mysteries of TRP channels in latest Perspectives series
10. CSHL researchers identify gene that helps plant cells keep communication channels open
11. Site used by sodium to control sensitivity of certain potassium ion channels
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Chloride channels render nerve cells more excitable
(Date:5/16/2017)...  Veratad Technologies, LLC ( www.veratad.com ), an innovative ... verification solutions, announced today they will participate as a ... thru May 17, 2017, in Washington D.C.,s ... Identity impacts the lives of billions ... evolving digital world, defining identity is critical to nearly ...
(Date:4/18/2017)... SUNNYVALE, Calif. , April 18, 2017  Socionext Inc., a ... prototype of a media edge server, the M820, which features the ... face recognition software provided by Tera Probe, Inc., will be showcased ... and at the NAB show at the Las Vegas ... ...
(Date:4/11/2017)... Research and Markets has announced the addition ... their offering. ... tracking market to grow at a CAGR of 30.37% during the ... 2017-2021, has been prepared based on an in-depth market analysis with ... its growth prospects over the coming years. The report also includes ...
Breaking Biology News(10 mins):
(Date:10/11/2017)... TX (PRWEB) , ... October 11, 2017 , ... ... August compared the implantation and pregnancy rates in frozen and fresh in ... contribution of progesterone and maternal age to IVF success. , After comparing the ...
(Date:10/10/2017)... ... 2017 , ... Dr. Bob Harman, founder and CEO of VetStem Biopharma, ... The event entitled “Stem Cells and Their Regenerative Powers,” was held on ... DVM, MPVM was joined by two human doctors: Peter B. Hanson, M.D., Chief of ...
(Date:10/9/2017)... DIEGO , Oct. 9, 2017  BioTech ... biological mechanism by which its ProCell stem cell ... critical limb ischemia.  The Company, demonstrated that treatment ... amount of limbs saved as compared to standard ... the molecule HGF resulted in reduction of therapeutic ...
(Date:10/7/2017)... ... October 06, 2017 , ... ... applications consulting for microscopy and surface analysis, Nanoscience Instruments is now expanding ... offers a broad range of contract analysis services for advanced applications. Services ...
Breaking Biology Technology: