Featured Research

from universities, journals, and other organizations

Some Brain Cells 'Change Channels' To Fine-tune The Message

Date:
May 28, 2005
Source:
Johns Hopkins Medical Institutions
Summary:
Johns Hopkins researchers have identified the proteins that allow specific brain cells to "change channels," a rare ability that tweaks what can come into the cell. The findings, described in the March 24 issue of Neuron, may let researchers harness the process, perhaps one day using it to protect cells that die in Lou Gehrig's disease.

Johns Hopkins researchers have identified the proteins that allow specific brain cells to "change channels," a rare ability that tweaks what can come into the cell. The findings, described in the March 24 issue of Neuron, may let researchers harness the process, perhaps one day using it to protect cells that die in Lou Gehrig's disease.

Much as turning the television dial changes what comes into the living room, these brain cells are able to change what they allow in by swapping one kind of channel, or membrane opening, for another. Doing so lets the cells fine-tune their messages and adjust connections within the cerebellum, the brain region that controls fine motor skills.

Although the cells' channel-changing ability has been recognized for a few years, the key players controlling it hadn't been identified. Now, by studying mice, the Hopkins team has identified two proteins, called PICK1 and NSF for short, that help replace channels that let charged calcium ions in with another kind of channel that keeps calcium out. If muscle-controlling nerve cells can do the same thing, forcing the swap might help protect them from a calcium overdose that can kill them in Lou Gehrig's disease.

"We don't know yet whether this happens in muscle-controlling nerve cells, but we're looking into it," says Richard Huganir, Ph.D., professor of neuroscience and a Howard Hughes Medical Institute investigator in Johns Hopkins' Institute for Basic Biomedical Sciences.

So far, no one has really looked for the channel changing in other cells in the brain, he says, in part because the swapped channels are most common in these particular cells in the cerebellum (so-called stellate cells). But Huganir thinks the channel changing is going to be relatively common in the brain.

Whether through channel changing or other, more well-understood ways of fine-tuning its responsiveness, a brain cell's activity level depends on its neighbors, the nerves and other cells that connect to it. Although they don't physically touch, the cell and its neighbor are so close to one another at these connection points, called synapses, that molecules released from one cell travel immediately to the next.

These molecules dock at specific places, or receptors, on the cell and trigger "channels" in the cell's membrane to open. Depending on the receptor and the channel, in will flow sodium, calcium, chloride or other charged atoms that then keep the communication process going.

In the cells in the cerebellum, a channel made of proteins called AMPA receptors, built from subunits called GluR3 and GluR4, is usually found at the synapse. If the cells are shocked with an electric current, within minutes the channels are replaced by ones made of GluR2 and GluR3. After the swap, sodium can still get in, but calcium is kept out.

To learn more about how this takes place, the Hopkins researchers studied brain cells from genetically engineered mice. Through their experiments, the researchers determined that the PICK1 and NSF proteins are both required for the calcium-forbidding channel to move into place at the synapse. Exactly how they help the channels move is still unknown, as is why the cells change their channels.

Part of the answer is likely to be self-preservation: Too much calcium inside nerve cells can kill them. But Huganir points out that calcium does a lot of things inside cells, suggesting that the channel swap might be accomplishing more than just keeping the cell alive. "Calcium turns some processes on, and it turns others off," he says. "My personal belief is that the cells might be doing more than just protecting themselves by keeping calcium out."

In some cases, protection might be enough of a goal. In people with Lou Gehrig's disease, or amyotrophic lateral sclerosis (ALS), some muscle-controlling nerve cells die because too much of the brain chemical glutamate binds to the cells' AMPA receptors, and so too much calcium gets inside. If these threatened nerve cells can swap their calcium-allowing channels for the kind that keeps calcium out, it might be possible to harness that switch to prevent the cells from dying. "But that's a big 'if' at this point," says Huganir.

###

The researchers were funded by the Robert Packard Center for ALS Research at Johns Hopkins, the National Institute of Neurological Disease and Stroke, and the Howard Hughes Medical Institute.

Authors on the paper are Huganir, Stephanie Gardner, Kogo Takamiya, Jun-Gyo Suh, Richard Johnson, Sandy Yum and Jun Xia, all of Johns Hopkins. Suh is now at the Hallym [sic] University College of Medicine, Chuncheon, Gangwondo, South Korea, and Xia is now at the Hong Kong University of Science and Technology.

Under a licensing agreement between Upstate Group Inc. and The Johns Hopkins University, Huganir is entitled to a share of royalty received by the University on sales of products used in this research. Huganir is a paid consultant to Upstate Group Inc. The terms of this arrangement are being managed by The Johns Hopkins University in accordance with its conflict of interest policies.


Story Source:

The above story is based on materials provided by Johns Hopkins Medical Institutions. Note: Materials may be edited for content and length.


Cite This Page:

Johns Hopkins Medical Institutions. "Some Brain Cells 'Change Channels' To Fine-tune The Message." ScienceDaily. ScienceDaily, 28 May 2005. <www.sciencedaily.com/releases/2005/05/050528120806.htm>.
Johns Hopkins Medical Institutions. (2005, May 28). Some Brain Cells 'Change Channels' To Fine-tune The Message. ScienceDaily. Retrieved July 31, 2014 from www.sciencedaily.com/releases/2005/05/050528120806.htm
Johns Hopkins Medical Institutions. "Some Brain Cells 'Change Channels' To Fine-tune The Message." ScienceDaily. www.sciencedaily.com/releases/2005/05/050528120806.htm (accessed July 31, 2014).

Share This




More Health & Medicine News

Thursday, July 31, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Dangerous Bacteria Kills One in Florida

Dangerous Bacteria Kills One in Florida

AP (July 31, 2014) Sarasota County, Florida health officials have issued a warning against eating raw oysters and exposing open wounds to coastal and inland waters after a dangerous bacteria killed one person and made another sick. (July 31) Video provided by AP
Powered by NewsLook.com
Health Insurers' Profits Slide

Health Insurers' Profits Slide

Reuters - Business Video Online (July 30, 2014) Obamacare-related costs were said to be behind the profit plunge at Wellpoint and Humana, but Wellpoint sees the new exchanges boosting its earnings for the full year. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com
Peace Corps Pulls Workers From W. Africa Over Ebola Fears

Peace Corps Pulls Workers From W. Africa Over Ebola Fears

Newsy (July 30, 2014) The Peace Corps is one of several U.S.-based organizations to pull workers out of West Africa because of the Ebola outbreak. Video provided by Newsy
Powered by NewsLook.com
Weather Kills 2K A Year, But Storms Aren't The Main Offender

Weather Kills 2K A Year, But Storms Aren't The Main Offender

Newsy (July 30, 2014) Health officials say 2,000 deaths occur each year in the U.S. due to weather, but it's excessive heat and cold that claim the most lives. Video provided by Newsy
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:
from the past week

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