Featured Research

from universities, journals, and other organizations

How Receptors Govern Inflammatory Pain

Date:
December 2, 2004
Source:
Cell Press
Summary:
Researchers have shown in animal studies how receptors on nerve cells can become altered to produce chronic pain triggered by inflammation. They say that their findings could aid in developing new drugs to treat such chronic pain, which is distinct from the relatively short-lived pain from injury, which fades as the injury heals.

Researchers have shown in animal studies how receptors on nerve cells can become altered to produce chronic pain triggered by inflammation. They say that their findings could aid in developing new drugs to treat such chronic pain, which is distinct from the relatively short-lived pain from injury, which fades as the injury heals.

In their experiments, Bettina Hartmann and her colleagues studied receptors called AMPA receptors, which are triggered by the neurotransmitter glutamate. Such receptors are protein switches that nestle in the membranes of nerve cells and, when triggered, induce either short-term or long-term changes in the nerve cells. A short-term change might be the triggering of a single nerve impulse; but AMPA receptors have been implicated in long-lasting changes such as adjusting the strength of nerve cell connections, or synapses, in learning and memory. AMPA receptors regulate nerve cell response by opening to enhance calcium flow into the cell, heightening the cells' sensitivity to producing nerve impulses when triggered.

According to Hartmann and her colleagues, studies of spinal cord tissue showed that AMPA receptors are found in spinal cord regions known to be responsible for pain sensing, or nociception. However, they said, there had been no studies that explored what role the receptors played in whole animals.

To study that role, the researchers genetically altered mice to lack one or another type of key component, or subunit, of the AMPA receptor protein. Knocking out one type of subunit, called GluR-A, would enhance AMPA permeability to calcium; and knocking out the other, called GluR-B, would reduce its permeability. Normally, the relative fraction of AMPA receptors with GluR-A or GluR-B on the surfaces of nerve cells would determine the cell's permeability to calcium.

Importantly, the researchers found that both of the types of deficient mice showed normal response to discomforting stimuli, such as heat. Thus, their pain responses were otherwise normal.

However, when the researchers used chemicals to induced an artificial inflammation in the paws of the deficient mice, they found significant differences in responses between the two mutant mouse strains. The strain with increased permeability of their AMPA channels was significantly more sensitive to heat or mechanical pressure on their inflamed paws than were either the strain of mice with "closed" AMPA channels or the normal mice.

In similar tests, the researchers also found that the altered mice with more permeable AMPA channels showed evidence of greater persisting pain from inflammation, compared with the altered mice with less permeable channels. According to Hartmann and her colleagues, this difference "supports that acute, short-term plasticity at central nociceptive synapses is dependent on AMPA receptors and their composition."

The researchers also cited evidence from other laboratories that AMPA receptors might be involved in pain-related changes in the brain that are "involved in the perception, memory, and emotional modulation of pain."

The researchers concluded that "the present study demonstrates that AMPA receptors are important determinants of pathological nociceptive sensitivity and suggests their potential relevance in the therapeutic approaches toward the prevention and treatment of chronic inflammatory pain.

Bettina Hartmann, Seifollah Ahmadi, Paul A. Heppenstall, Gary R. Lewin, Claus Schott, Thilo Borchardt, Peter H. Seeburg, Hanns Ulrich Zeilhofer, Rolf Sprengel, and Rohini Kuner: "The AMPA Receptor Subunits GluR-A and GluR-B Reciprocally Modulate Spinal Synaptic Plasticity and Inflammatory Pain"

Publishing in Neuron, Volume 44, Number 4, November 18, 2004, pages 637–650. http://www.neuron.org.


Story Source:

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


Cite This Page:

Cell Press. "How Receptors Govern Inflammatory Pain." ScienceDaily. ScienceDaily, 2 December 2004. <www.sciencedaily.com/releases/2004/11/041123163648.htm>.
Cell Press. (2004, December 2). How Receptors Govern Inflammatory Pain. ScienceDaily. Retrieved August 28, 2014 from www.sciencedaily.com/releases/2004/11/041123163648.htm
Cell Press. "How Receptors Govern Inflammatory Pain." ScienceDaily. www.sciencedaily.com/releases/2004/11/041123163648.htm (accessed August 28, 2014).

Share This




More Health & Medicine News

Thursday, August 28, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Mini Pacemaker Has No Wires

Mini Pacemaker Has No Wires

Ivanhoe (Aug. 27, 2014) Cardiac experts are testing a new experimental device designed to eliminate major surgery and still keep the heart on track. Video provided by Ivanhoe
Powered by NewsLook.com
After Cancer: Rebuilding Breasts With Fat

After Cancer: Rebuilding Breasts With Fat

Ivanhoe (Aug. 27, 2014) More than 269 million women are diagnosed with breast cancer each year. Many of them will need surgery and radiation, but there’s a new simple way to reconstruct tissue using a patient’s own fat. Video provided by Ivanhoe
Powered by NewsLook.com
Blood Clots in Kids

Blood Clots in Kids

Ivanhoe (Aug. 27, 2014) Every year, up to 200,000 Americans die from a blood clot that travels to their lungs. You’ve heard about clots in adults, but new research shows kids can get them too. Video provided by Ivanhoe
Powered by NewsLook.com
Radio Waves Knock out Knee Pain

Radio Waves Knock out Knee Pain

Ivanhoe (Aug. 27, 2014) Doctors have used radio frequency ablation or RFA to reduce neck and back pain for years. But now, that same technique is providing longer-term relief for patients with severe knee pain. Video provided by Ivanhoe
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