Serotonin receptor is involved in eczema and other itch conditions

June 11, 2015
This mouse was involved in the study which identified serotonin receptor HTR7 as a key mediator of chronic itch. Credit: Courtesy of Diana Bautista, UC Berkeley

Dermatologists have long known that available treatments for chronic itch, including eczema, are simply not up to scratch. But scientists have now discovered a new gene that promotes itch, suggesting a way forward for powerful new therapies. In a paper published June 11 in the early-online edition of Neuron, researchers at the Buck Institute for Research on Aging and the University of California, Berkeley have identified a serotonin receptor, HTR7, as a key mediator of eczema and other forms of itch. Eczema is a debilitating condition that affects up to 10 percent of the worldwide population. Its symptoms include intense itch sensations, dry flaky skin, and a flaming red rash. Eczema can erode quality of life as dramatically as chronic pain does, and is incurable, and treatments to manage eczema are often not effective. But now, the Buck/Berkeley team has identified a new gene that may accelerate development of chronic itch therapies.

The work involved a collaboration between UC Berkeley neuroscientist Diana Bautista, Ph.D., who runs a lab focused on the molecular basis of the sensations of itch, touch and pain, and Buck Associate Professor Rachel Brem, Ph.D., a geneticist who studies how and why traits differ between individuals. Bautista, Brem, and collaborators sought out genes whose expression was correlated with itch behavior across genetically distinct mouse strains. The , HTR7, caught the scientists' attention because the itchiest mice expressed the most HTR7 in the neurons that innervate the skin, and because abnormal serotonin signaling has long been linked to a variety of human disorders, including eczema.

A battery of follow-up experiments then validated the role of HTR7 in chronic itch. In a mouse model of eczema, loss of the HTR7 gene in mice led to significantly less scratching and less severe skin lesions. 'We are really excited about these results. The dramatic decrease in itching suggests that HTR7 may represent a new drug target for chronic itch,' said Bautista, who is an associate professor in the Department of Molecular and Cell Biology and a member of the Helen Wills Neuroscience Institute at UC Berkeley.

Brem says that, in addition to eczema, altered serotonin signaling in the skin is found in other forms of itch, including psoriasis and allergic itch. Therefore, the new findings hold promise for treatment of many itch disorders. In fact, in humans, itching and scratching can be side effects of taking antidepressants, which can elevate levels of serotonin in the skin. In the Buck/UC Berkeley study, this side effect was observed in mice, too—the drug Zoloft caused intense scratching, which vanished when HTR7 was ablated. Given that in humans HTR7 is also expressed in the neurons that innervate the skin, this new gene may well be responsible for itch in human patients taking antidepressants.

'An estimated 10 to 20 percent of the population will suffer from chronic itch at some point in their lifetime,' said Brem. 'In addition to , chronic itch can stem from systemic conditions including kidney failure, cirrhosis and some cancers. Understanding the molecular basis of chronic itch is of significant clinical interest, and now there is a new target available to explore.'

Explore further: Blocking nerve cells could prevent symptoms of eczema

More information: HTR7 mediates serotonergic acute and chronic itch, Neuron, 2015.

Related Stories

Blocking nerve cells could prevent symptoms of eczema

October 3, 2013
A new picture of how the nervous system interacts with the immune system to cause the itch and inflammation associated with eczema, a chronic skin disease, could lead to new therapies for the condition, according to University ...

Neuroscience: Why scratching makes you itch more

October 30, 2014
Turns out your mom was right: Scratching an itch only makes it worse. New research from scientists at Washington University School of Medicine in St. Louis indicates that scratching causes the brain to release serotonin, ...

Scientists unravel mechanisms in chronic itching

October 15, 2013
Anyone who has suffered through sleepless nights due to uncontrollable itching knows that not all itching is the same. New research at Washington University School of Medicine in St. Louis explains why.

These scientists are 'itching' to help you stop scratching

June 5, 2013
Itch and scratch, itch and scratch. It's not the most serious physical problem in our lives, but it is common and it is very annoying. Now, researchers at the Hebrew University of Jerusalem and in Boston have come up with ...

Body location plays part in scratching pleasure

January 27, 2012
An itch is just an itch. Or is it? New research from Gil Yosipovitch, M.D., Ph.D., professor of dermatology at Wake Forest Baptist Medical Center and a world-renowned itch expert, shows that how good scratching an itch feels ...

Itching can have a visual trigger, new research reveals

November 25, 2012
(Medical Xpress)—Itching is so contagious that simply seeing an image of an itch stimulus – such as ants or an insect bite – can trigger a physical response, new research suggests.

Recommended for you

Small but distinct differences among species mark evolution of human brain

November 23, 2017
The most dramatic divergence between humans and other primates can be found in the brain, the primary organ that gives our species its identity.

Team constructs whole-brain map of electrical connections key to forming memories

November 22, 2017
A team of neuroscientists at the University of Pennsylvania has constructed the first whole-brain map of electrical connectivity in the brain based on data from nearly 300 neurosurgical patients with electrodes implanted ...

To forget or to remember? Memory depends on subtle brain signals, scientists find

November 22, 2017
The fragrance of hot pumpkin pie can bring back pleasant memories of holidays past, while the scent of an antiseptic hospital room may cause a shudder. The power of odors to activate memories both pleasing and aversive exists ...

Pitch imperfect? How the brain decodes pitch may improve cochlear implants

November 22, 2017
Picture yourself with a friend in a crowded restaurant. The din of other diners, the clattering of dishes, the muffled notes of background music, the voice of your friend, not to mention your own – all compete for your ...

New research suggests high-intensity exercise boosts memory

November 22, 2017
The health advantages of high-intensity exercise are widely known but new research from McMaster University points to another major benefit: better memory.

Schizophrenia originates early in pregnancy, 'mini-brain' research suggests

November 20, 2017
Symptoms of schizophrenia usually appear in adolescence or young adulthood, but new research reveals that the brain disease likely begins very early in development, toward the end of the first trimester of pregnancy. The ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.