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:4/11/2017)... , April 11, 2017 Crossmatch®, ... secure authentication solutions, today announced that it has ... Advanced Research Projects Activity (IARPA) to develop next-generation ... program. "Innovation has been a driving ... Thor program will allow us to innovate and ...
(Date:4/6/2017)... LONDON , April 6, 2017 ... Control, RFID, ANPR, Document Readers, by End-Use (Transportation & ... Energy Facility, Oil, Gas & Fossil Generation Facility, Nuclear ... Healthcare, Educational, Other) Are you looking for ... Authentication sector? ...
(Date:4/4/2017)... NEW YORK , April 4, 2017   ... solutions, today announced that the United States Patent and ... The patent broadly covers the linking of an iris ... the same transaction) and represents the company,s 45 th ... our latest patent is very timely given the multi-modal ...
Breaking Biology News(10 mins):
(Date:10/11/2017)... , ... October 11, 2017 , ... ... announced today it will be hosting a Webinar titled, “Pathology is going digital. ... Associates , on digital pathology adoption best practices and how Proscia improves lab ...
(Date:10/11/2017)... ... October 11, 2017 , ... ... granted orphan drug designation to SBT-100, its novel anti-STAT3 (Signal Transducer and Activator ... osteosarcoma. SBT-100 is able to cross the cell membrane and bind intracellular STAT3 ...
(Date:10/10/2017)... , Oct. 10, 2017 International research firm Parks ... Strategy, will speak at the TMA 2017 Annual Meeting , October ... trends in the residential home security market and how smart safety and ... Parks ... "The residential ...
(Date:10/9/2017)... FL (PRWEB) , ... October 09, 2017 , ... The ... scheduled to broadcast first quarter 2018. American Farmer airs Tuesdays at 8:30aET on RFD-TV. ... industry is faced with the challenge of how to continue to feed a growing ...
Breaking Biology Technology: