Medicine Nobel awarded for explaining how we sense heat and touch

David Julius, Ardem Patapoutian Niklas Elmehed/ Nobel Prize Outreach
Ardem Patapoutian and David Julius were awarded the 2021 Nobel prize in physiology or medicine for their discoveries about how cells sense temperature and touch.

Thomas Perlmann, secretary of the Nobel committee said that this unlocks one of nature's secrets. This molecular explanation explains how stimuli can be converted to nerve signals. This is vital for our survival.

It is essential to be able to sense heat and pressure. However, we don't know how nerve cells can detect heat or touch.


David Julius, University of California, San Francisco, discovered how nerve cells sense heat by using the fact that chillies contain capsaicin, which activates heat receptors. His team took DNA from genes that were active in sensory cells, and added fragments of the DNA to cells that don't normally respond to capsaicin.

They tested thousands of fragments to determine which allowed the cells to respond to capsaicin and make the receptor. Finally, they discovered a protein called TRPV1 (that codes for an ion channels that is found in nerve cells). Higher temperatures can open the ion channels, causing a voltage change that causes the nerve fire to produce heat.

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Julius and Ardem Patapoutian led teams at Scripps Research, La Jolla, California. They then independently discovered TRPM8 which opens when it is cold, rather than heat. These cold receptors are activated by menthol, which was discovered by both teams. Since then, several similar ion channels were discovered that allow for a wide range of temperatures to be sensed.

Patapoutians used cells that emit an electrical signal when they were poked to identify touch receptors. They also discovered 270 genes that could code for touch receptor protein genes. These genes were then turned off in cells by the researchers one at a time.

They discovered PIEZO1, an ion-channel that opens when there is mechanical pressure. This allowed them to identify a protein similar to PIEZO2. These receptors allow the body to detect external touch and other factors such as blood pressure, bladder pressure, and breathing.

Perlmann stated that he spoke briefly with Julius and Patapoutian just before making the announcement. Although I only had a few moments to speak with them, they were extremely happy. He said that they were surprised and a little shocked by the announcement.

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