A new study conducted by the researchers at the National Institutes of Health claims to have revealed the mystery behind the itch. This study, conducted on mice, claims that a molecule called natriuretic peptide b (Nppb) is the actual culprit behind the itch.
This particular molecule sets in motion a series of reactions, leading to pruritus- a condition to which our brain reacts as an 'itch'.
"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 land line to the brain," senior author Mark Hoon, a scientist at the National Institute of Dental and Craniofacial Research, part of the NIH, said in a press release.
The Nppb, when gets into the brain and plugs into a nerve cell, it sends an 'itching' message to the central nervous system of the body, thereby causing the itch.
What's even more surprising is the fact that when the researchers removed Nppb or its nerve cell, they noticed that the mice stopped itching despite being exposed to a number of itch-causing factors.
"We tested Nppb for its possible role in various sensations without success," lead author Santosh Mishra, a researcher in Hoon's laboratory, said in the press release. "When we exposed the Nppb-deficient mice to several itch-inducing substances, it was amazing to watch. Nothing happened. The mice wouldn't scratch."
A similar procedure, if carried out in humans, could definitely prove to be a boon to patients suffering from itchy skin conditions such as eczema and psoriasis. However, there is a lot to be figured out to better understand and develop treatment options for chronic skin conditions. Also, considering that getting rid of the neurotransmitter may prove to be harmful to humans, and may lead to blood pressure problems, finding the cure may not be as easy as expected.
"The larger scientific point remains," Hoon explained. "We have defined in the mouse the primary itch-initiating neurons and figured out the first three steps in the pruritic pathway. 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."
