Molecular basis of temperature and pressure sensatiosn in humans decoded

David Julius’s and Ardem Patapoutian’s research on the genetic basis of the sensation of temperature and pressure has won them the 2021 Nobel Prize in Physiology or Medicine.

Food eaten at room temperature feels pleasant, however, when heated beyond a certain level, it feels hot and uncomfortable to the tongue and the mouth. When we eat hot chilies containing a chemical, capsaicin, a burning sensation is experienced by us. Well, what is extraordinary in it, everybody experiences it. The sensations of temperature and touch are so vital to us in day-to-day life that we take them for granted. Imagine if the sensation of temperature goes away, hot food eaten will not be noticed by us and we will burn our mouth. Therefore the painful stimuli that we feel, works as a natural safeguard to prevent potential harm to the body. It was earlier understood that the nerve endings perceived this feeling and conveyed it to the brain. However, how exactly this happens was not known?

The discoveries made by David Julius at the University of California, San Francisco, USA, for temperature receptors have solved this puzzle. Julius and his colleagues made experiments for the expression of millions of genes from the gene library and were able to identify a single gene encoding a novel ion channel capsaicin receptor  protein named as TRPV1.

Receptors for mechanical stimuli were identified by Ardem Patapoutian and co-workers, of Scripps Research in La Jolla, California. They discovered a new single gene coding for mechanosensitive ion channel protein and named it as Piezo1 but later on found another gene named Piezo2. Upon stimulation by pressure on the cell membranes, these two protein ion channels are activated and the sensation is transmitted to brain.

The discovery of another gene coding for a protein sensitive to cold (TRPM8) goes to the credit of both the Nobel Laureates, Julius and Patapoutian.

Future research in this direction can open new vistas in understanding the sensory abilities for hot, cold and pressure stimuli and also go a long way in the treatment and alleviation of chronic pain.