A team of scientists at Karolinska Institutet has discovered a previously unknown meshlike organ in the skin that is sensitive to painful mechanical damage, such as pricks and impacts.

Pain causes suffering and results in substantial costs for society. Almost one person in every five experiences constant pain and there is a considerable need to find new painkilling drugs.

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.

The newly-discovered sensory organ is built from specialized glial cells located in the epidermal-dermal border.

It is sensitive to painful mechanical damage such as pricks and pressure.

“Its activation results in electrical impulses in the nervous system, reflex reactions and an experience of pain,” said Professor Patrik Ernfors and colleagues.

“The glial cells that make up this organ are highly sensitive to mechanical stimuli, which explain how they can participate in the detection of painful pinpricks and pressure.”

In the study, 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 fibers, but also in this pain-sensitive organ,” Professor Ernfors said.

“The discovery changes our understanding of the cellular mechanisms of physical sensation and it may be of significance in the understanding of chronic pain.”

The discovery is reported in a paper in the journal Science.

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Hind Abdo et al. 2019. Specialized cutaneous Schwann cells initiate pain sensation. Science 365 (6454): 695-699; doi: 10.1126/science.aax6452