Neuroscientists find 'gatekeeper' in itching sensations plays no role in pain transmission

October 3, 2017 by D'lyn Ford
Pain and itch sensory neurons, shown in red. Credit: North Carolina State University

A study from North Carolina State University researchers shows that a neurotransmitter involved in relaying itching sensations from the skin to the spinal cord and into the brain plays no role in pain transmission.

"For us, it's very important to understand the neural circuits or pathways so that we can develop therapies specifically for pain or itch, instead of targeting it as a whole system," says Santosh Mishra, assistant professor of neuroscience in NC State's College of Veterinary Medicine and the corresponding author of a paper on the topic. "This work shines a light on these different pathways for pain and itch."

Mishra's team focused on a called natriuretic peptide (BNP), which is expressed in a small number of or neurons. Mishra's previous work at the National Institutes of Health established that, in mice, BNP is involved in transmitting itching sensations from the skin to the brain.

For this study, researchers looked at whether BNP played a role in transmitting acute, inflammatory or neuropathic pain in mice. Results were the same for regular mice and those that lacked the BNP gene. "That means BNP was not involved for any of these distinct types of pain," Mishra says. "We know that if we target BNP, we won't be inhibiting pain; we'll be inhibiting itch."

Pain or itching sensations begin when a nerve cell on the surface of the body reacts to a stimulus, starting a chain reaction that moves from cell to cell.

"Neurons react to a stimulus by depolarizing, which is how the talk to each other," Mishra says. "Once it's depolarized, a neuron releases a neurotransmitter, which starts the communication from one cell to another, moving from the periphery of the body to the central nervous system."

The neural pathway takes the message to the , which is connected to the brain. The brain interprets the signals from the nerves, creating the sensations of pain and itching.

"If we know how these sensations are transmitted, we can design specific drugs or therapies to block the neurotransmitters, block the receptors for the neurotransmitters or reduce the degree to which those neurotransmitters work," Mishra says. "I call these the gatekeepers because they are sitting in between the skin and the central nervous system."

The goal is to develop treatments that interrupt the pain or itch signals closer to the source.

"If we can block the sensation at the peripheral level, in the skin, that is a much friendlier way than to try to target the once it reaches the brain," Mishra says. "We know the importance of . Studying itching sensations is a relatively new field, but if we look at the number of diseases where itch is a major symptom, it includes not only atopic dermatitis but also nervous system disorders such as multiple sclerosis, as well as infection and end stage kidney disease. This work is an initial step in gaining a better understanding."

The paper, "Brain natriuretic peptide (BNP) expressing sensory neurons are not involved in acute, inflammatory or neuropathic " is published in the journal Molecular Pain

Explore further: Itch neurons play a role in managing pain

More information: "Brain natriuretic peptide (BNP) expressing sensory neurons are not involved in acute, inflammatory or neuropathic pain" Molecular Pain, DOI: 10.1177/1744806917736993 , http://journals.sagepub.com/doi/abs/10.1177/1744806917736993

Related Stories

Itch neurons play a role in managing pain

February 22, 2017
There are neurons in your skin that are wired for one purpose and one purpose only: to sense itchy things. These neurons are separate from the ones that detect pain, and yet, chemical-induced itch is often accompanied by ...

Scientists identify central neural circuit for itch sensation

August 17, 2017
Itching is an unpleasant sensation associated with the desire to scratch, and the itch sensation is an important protective mechanism for animals. However, chronic itch, often seen in patients with skin and liver diseases, ...

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.

Scientists discover molecule triggers sensation of itch

May 23, 2013
Scientists at the National Institutes of Health report they have discovered in mouse studies that a small molecule released in the spinal cord triggers a process that is later experienced in the brain as the sensation of ...

Potential new target identified for treating itch

July 19, 2016
Researchers have found how sensory nerve cells work together to transmit itch signals from the skin to the spinal cord, where neurons then carry those signals to the brain. Their discovery may help scientists find more effective ...

Recommended for you

LLNL-developed microelectrodes enable automated sorting of neural signals

December 13, 2017
Thin-film microelectrode arrays produced at Lawrence Livermore National Laboratory (LLNL) have enabled development of an automated system to sort brain activity by individual neurons, a technology that could open the door ...

Discovery deepens understanding of brain's sensory circuitry

December 12, 2017
Because they provide an exemplary physiological model of how the mammalian brain receives sensory information, neural structures called "mouse whisker barrels" have been the subject of study by neuroscientists around the ...

Intermittent fasting found to increase cognitive functions in mice

December 12, 2017
(Medical Xpress)—The Daily Mail spoke with the leader of a team of researchers with the National Institute on Aging in the U.S. and reports that they have found that putting mice on a diet consisting of eating nothing every ...

Stuttering: Stop signals in the brain disturb speech flow

December 12, 2017
One per cent of adults and five per cent of children are unable to achieve what most of us take for granted—speaking fluently. Instead, they struggle with words, often repeating the beginning of a word, for example "G-g-g-g-g-ood ...

Neuroscientists show deep brain waves occur more often during navigation and memory formation

December 12, 2017
UCLA neuroscientists are the first to show that rhythmic waves in the brain called theta oscillations happen more often when someone is navigating an unfamiliar environment, and that the more quickly a person moves, the more ...

How Zika virus induces congenital microcephaly

December 12, 2017
Epidemiological studies show that in utero fetal infection with the Zika virus (ZIKV) may lead to microcephaly, an irreversible congenital malformation of the brain characterized by an incomplete development of the cerebral ...

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.