Researchers have discovered a new sensory organ in the skin that is able to detect painful mechanical damage, such as pricks and impacts, an advance that may help develop novel painkillers.
Almost one person in every five experiences constant pain and there is a considerable need to find new painkilling drugs, according to research published in the journal Science.
However, sensitivity to pain is also required for survival and it has a protective function.
It prompts reflex reactions that prevent damage to tissue, such as pulling your hand away when you feel a jab from a sharp object or when you burn yourself.
Researchers at Karolinska Institutet in Sweden have now discovered a new sensory organ in the skin that is sensitive to hazardous environmental irritation.
It is comprised of glia cells with multiple long protrusions and which collectively go to make up a mesh-like organ within the skin.
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This organ is sensitive to painful mechanical damage such as pricks and pressure.
The new pain-sensitive organ is organised together with pain-sensitive nerves in the skin, researchers said.
Activation of the organ results in electrical impulses in the nervous system that result in reflex reactions and an experience of pain, they said.
The cells that make up the organ are highly sensitive to mechanical stimuli, which explain how they can participate in the detection of painful pinpricks and pressure.
In experiments, the researchers also blocked the organ and saw a resultant decreased ability to feel mechanical pain.
"Our study shows that sensitivity to pain does not occur only in the skin's nerve fibres, but also in this recently-discovered pain-sensitive organ," said Patrik Ernfors, a professor at Karolinska Institutet.
"The discovery changes our understanding of the cellular mechanisms of physical sensation and it may be of significance in the understanding of chronic pain," Ernfors said.