Navigation Links
Itching Not a Less Intense Form of Pain

Each are regulated by different molecular mechanisms, scientists show

TUESDAY, Nov. 18 (HealthDay News) -- Pain and itching are regulated by different molecular mechanisms, according to a Washington University study that challenges the long-held belief that itching is a less intense version of the body's response to pain.

This finding could prove important in improving treatment of chronic itching and pain.

Zhou-Feng Chen, of Washington University's Pain Center, in St. Louis, and colleagues found that pain signals are not affected in mice bred without an itch gene called gastrin-releasing peptide receptor (GRPR) or when the gene's actions are blocked. When the mice without the GRPR gene were exposed to itchy stimuli, they scratched less than normal mice.

GRPR, previously identified by the same team of researchers, makes a receptor found in a small number of nerve cells in a region of the spinal cord that transmits itch and pain signals, as well as temperature sensation, from the skin to the brain.

"There are two major types of itching," explained Chen, an associate professor of anesthesiology, psychiatry and developmental biology. Histamine-dependent itching is caused by bug bites or allergic reactions and can be treated with antihistamine drugs. Chronic, severe itching often occurs as a side effect of spinal injections of opioid drugs, such as morphine, given to chronic pain patients. This type of itching can't be relieved by antihistamines.

"Most scientists believed that the itching could not be separated from the drug's pain-killing effects," Chen said. But he and his team thought GRPR may be responsible for the itching but involved in the pain response.

"If we inject a GRPR inhibitor and morphine into the mouse spinal cord, the drug still has its normal analgesic effect, but the mice don't scratch. This is very interesting, because it demonstrates that analgesia and itching can be separated. There may be itch-specific genetic pathways in the spinal cord that are not related to pain sensation," Chen said.

Like mice, humans also have GRPR genes, so it may be possible to treat chronic itching in humans using a similar approach.

"Our findings could have important therapeutic implications. More research needs to be done, but it may be possible to relieve itching in patients by blocking GRPR function without affecting the pain pathway," Chen said.

The study was presented Monday at the Society for Neuroscience annual meeting, in Washington, D.C.

More information

The American Academy of Dermatology has more about itching.

-- Robert Preidt

SOURCE: Washington University School of Medicine in St. Louis, news release, Nov. 17, 2008

Copyright©2008 ScoutNews,LLC.
All rights reserved  

Related medicine news :

1. Walgreens Pays $35 Million, Settles Pharmacist-Whistleblower Qui Tam Drug Switching Allegations
2. Attorney General Corbett Announces $36.7 Million Multi-State Settlement With CVS/Caremark in National Dosage-Switching Investigation
3. CVS, Americas Largest Pharmacy Chain, Pays Nearly $37 Million to Settle Federal and State Generic Drug Switching Charges
4. Playing Catch in Winter Could Save Kids Pitching Arms
5. How pitching changes little leaguers shoulders
6. Switching to MA Coverage Unlikely for Current Beneficiaries With MediGap or Medicare Only
7. Ultra-fast, ultra-intense laser has clean-cut advantage
Post Your Comments:
Related Image:
Itching Not a Less Intense Form of Pain
(Date:11/30/2015)... ... 30, 2015 , ... The Progressive Dental Institute ... 29 and 30, 2016. The course welcomes dental professionals and members of their ... how to better succeed in the modern dental marketplace. The course combines presentations ...
(Date:11/30/2015)... , ... November 30, 2015 , ... ... key disease-causing component of bacteria could be effective in fighting methicillin-resistant Staphylococcus aureus ... State University. , Their study showed that small molecule analogs that target the ...
(Date:11/30/2015)... NJ (PRWEB) , ... November 30, 2015 , ... Dr. ... With three office locations, patients can visit Dr. Margulies to experience the best available ... to hold the title of "NJ Top Dentist"! , Orthodontics is the branch of ...
(Date:11/30/2015)... ... November 30, 2015 , ... ”Dying Words: The AIDS Reporting ... on December 1, 2015, to coincide with World AIDS Day. The multi-media project will ... covered the AIDS epidemic as he was dying of the disease. , A collaborative ...
(Date:11/30/2015)... ... November 30, 2015 , ... According to RF Safe, the ... scientist at Consumer Reports as supporting a “A Call for Clarity” on cell ... The original Nov 2015 CR story titled, “Does Cell-Phone Radiation Cause Cancer?” ...
Breaking Medicine News(10 mins):
(Date:11/30/2015)... -- Kevin Smith has been appointed Chief Commercial Officer ... wireless monitoring of vital signs.  As CCO based ... Smith will be responsible for the development and ... also directly oversee partnering with US hospitals and ... the first early warning detection device to be ...
(Date:11/30/2015)... Nov. 30, 2015  The fee-for-service reimbursement ... U.S. medical imaging is on its way ... care payer-provider contracts are set to phase ... wake, alter provider-vendor relationships. The shift to ... forward new purchasing frameworks in the medical ...
(Date:11/30/2015)... SAN DIEGO , Nov. 30, 2015 ... ARNA ) today announced that the U.S. Food ... New Drug Application (NDA) for an extended release formulation ... offer patients a chronic weight management treatment in a ... currently approved as an adjunct to a reduced-calorie diet ...
Breaking Medicine Technology: