Navigation Links
Got an Itch? Mouse Study May Help Explain Why

THURSDAY, May 23 (HealthDay News) -- The sensation of itching is hardwired into the nervous system and can be traced back to a small molecule released in the spinal cord, according to a new study in mice.

Researchers say this molecule, known as natriuretic polypeptide b (Nppb), triggers a signal that passes through the central nervous system. Ultimately, this signal is experienced as an itch. Since the nervous systems of humans and mice are similar, the researchers concluded that a similar process probably occurs in people.

"Our work shows that itch, once thought to be a low-level form of pain, is a distinct sensation that is uniquely hardwired into the nervous system with the biochemical equivalent of its own dedicated landline to the brain," study senior author Mark Hoon, a scientist at the U.S. National Institute of Dental and Craniofacial Research, said in an institute news release.

The findings might someday help scientists develop treatments for chronic itch conditions, such eczema and psoriasis, the researchers suggested.

For the new study, the researchers first identified the signaling components on nerve cells that contain a molecule called TRPV1. These nerve cells help to monitor certain external conditions, such as extreme temperature changes or detecting pain. In examining how these cells recognize various sensations, the study authors screened the molecule, Nppb.

"We tested Nppb for its possible role in various sensations without success," study lead author Santosh Mishra, a researcher in the Hoon laboratory, said in the news release. However, he added, "When we exposed the Nppb-deficient mice to several itch-inducing substances, it was amazing to watch. Nothing happened. The mice wouldn't scratch."

When Nppb or its nerve cell was not present, mice stopped scratching because the signal wasn't going through, the researchers explained.

The investigators also focused on the dorsal horn, an area of the spine where sensory signals from the body are routed to the brain in order to look for cells that receive incoming Nppb molecules. They identified the receptor as the protein Npra.

"The receptors were exactly in the right place in the dorsal horn," noted Hoon. "We went further and removed the Npra neurons from the spinal cord. We wanted to see if their removal would short-circuit the itch, and it did."

Because removing the receptor nerve cells did not affect other sensations -- such as temperature, pain and touch -- the researchers concluded there is a dedicated signal to the brain that conveys the sensation of itch. Although another neurotransmitter called GRP also plays a role in the sensation of itch, they pointed out that it becomes involved only after Nppb triggers the process.

However, since the Nppb molecule is also used by the heart, kidneys and other parts of the body, the researchers concluded that attempting to control itch through the neurotransmitter in the spine could have negative side effects.

"The larger scientific point remains," Hoon said. "Now the challenge is to find similar biocircuitry in people, evaluate what's there, and identify unique molecules that can be targeted to turn off chronic itch without causing unwanted side effects. So, this is a start, not a finish."

Research in animals often doesn't translate into success in human studies.

The study appeared online May 23 in the journal Science.

More information

The U.S. National Library of Medicine has more about itching.

-- Mary Elizabeth Dallas

SOURCE: U.S. National Institute of Dental and Craniofacial Research, news release, May 23, 2013

Copyright©2012 ScoutNews,LLC.
All rights reserved  

Related medicine news :

1. Mouse Study Hints at New Path for Diabetes Treatment
2. This mousetrap may save lives
3. Its Not Just What You Eat, Its When You Eat, Mouse Study Finds
4. Belly Membrane May Regulate Immune System, Mouse Study Finds
5. Mouse Study Suggests Certain Fats Could Trigger Crohns, Colitis
6. New mouse model helps explain gene discovery in congenital heart disease
7. TB treatment paradox: Mouse studies show bodys own response helps TB bacteria survive
8. Scientists develop mouse model that could lead to new therapies for liver cancer
9. Mouse With Human-Like Immune System Could Advance AIDS Research
10. A CNIO team creates a unique mouse model for the study of aplastic anaemia
11. Mouse model exposes a new type of T cell to target melanoma
Post Your Comments:
Related Image:
Got an Itch? Mouse Study May Help Explain Why
(Date:10/13/2017)... , ... October 13, 2017 , ... ... serving communities in the greater Dallas, Miami, and Raleigh regions, is organizing an ... to overcome a rare and deadly chromosome abnormality. , After struggling since birth ...
(Date:10/13/2017)... ... 13, 2017 , ... While it’s often important to take certain medications during ... Austin, Texas, has identified a solution. , She developed a prototype for MOTION LIGHT-UP ... such, it eliminates the need to turn on a light when taking medication during ...
(Date:10/13/2017)... , ... October 13, 2017 , ... PurhealthRX , ... Oil utilizing Purzorb™ technology. Applying the Purzorb™process to full spectrum CBD oil will revolutionize ... providing a CBD form that can be easily incorporated into liquid products, while reducing ...
(Date:10/13/2017)... ... 13, 2017 , ... Apple Rehab Shelton Lakes , which specializes in ... the facility as part of a disaster drill on October 3rd. , Apple Rehab ... City Emergency Manager, as well as the Connecticut Long Term Care Mutual Aid ...
(Date:10/13/2017)... New York, NY (PRWEB) , ... October 13, 2017 , ... ... most influential people in business to advocate for action towards gender equality at their ... 18,000 views from around the globe, and reached a social audience of over 3 ...
Breaking Medicine News(10 mins):
(Date:10/11/2017)... IRVING, Texas , Oct. 11, 2017  Caris ... science focused on fulfilling the promise of precision medicine, ... Institute has joined Caris, Precision Oncology Alliance™ (POA) as ... leading cancer centers, the St. Jude Crosson Cancer Institute ... to advance the use of tumor profiling, making cancer ...
(Date:10/7/2017)... , Oct. 6, 2017   Provista, a ... than $100 billion in purchasing power, today announced a ... information. The Newsroom is the online home ... trends, infographics, expert bios, news releases, slideshows and events. ... to a wealth of resources at their fingertips, viewers ...
(Date:10/2/2017)... 2017 Diplomat Pharmacy, Inc. (NYSE: ... Consulting, LLC , and named its founder as Diplomat,s ... Tennessee , will operate under Diplomat ... service offerings for health care partners to include IT ... "In an interoperable world, technology delivers comprehensive ...
Breaking Medicine Technology: