Swedish researchers have discovered a new sensory organ in the skin that 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, says researchers at Karolinska Institutet.

"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.

In experiments, the researchers also blocked the organ and saw a resultant decreased ability to feel mechanical pain.

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. The discovery of the previously unknown pain-sensing organ could lead to the development of new painkilling drugs.

The team found that these Schwann cells—main "supporting cells" of the peripheral nervous system which wrap around axons of motor and sensory neurons—are octopus-shaped. The body of the cells lies beneath the outer layer of the skin, and there are longer extensions around the edge of the nerve cells that are pain sensitive, extending up into the epidermis, the outer layer of the skin. Thus it collectively go to make up a mesh-like organ within the skin and remains sensitive to painful mechanical damage such as pricks and pressure.

Sensitivity to pain is 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.

Activation of the organ results in electrical impulses in the nervous system that result in reflex reactions and an experience of pain, the researchers said.

(With PTI inputs)