This year’s Nobel Prize for Physiology or Medicine — awarded to the researchers, David Julius and Ardem Patapoutian from the University of California, San Francisco and Scripps Research in La Jolla, California, respectively — recognises their seminal work in identifying the gene and understanding the mechanism through which our body perceives temperature and pressure . Our ability to sense touch and temperature — particularly noxious temperature — is essential for our survival and determines how we interact with our internal and external environment; chronic pain results when the pain response goes awry. Dr. Julius utilised capsaicin, a key ingredient in hot chilli peppers that induces a burning sensation, to identify a sensor in the nerve endings of the skin and the cellular mechanism that responds to uncomfortably hot temperatures. The receptor for heat gets activated only above 40° C, which is close to the psychophysical threshold for thermal pain, thus allowing us to react to external heat. In 2002, five years after the heat sensor was discovered, the two laureates, and independently, used menthol to discover the receptor that senses cold temperatures. Recent studies have found that discrimination between warm and cool temperatures is possible only through simultaneous activation of warmth-sensing nerve fibres and inhibition of cold-sensing nerve fibres. Using pressure-sensitive cells, Dr. Patapoutian discovered a novel class of mechanical sensors that responds to pressure on the skin and internal organs, and the perception of touch and proprioception — the ability to feel the position and movement of our body parts. The cellular mechanism that senses touch also regulates important physiological processes. Besides laboratory work, insights have been gained by studying people carrying genetic mutations in the cellular mechanism of temperature, pain, touch and pressure sensation.
The discovery of pain receptors and the cellular mechanism have attracted pharmaceutical companies as these could be targets for novel medicines. Though there are challenges to be addressed before such drugs can be clinically meaningful, the hope is that newer approaches may one day bypass the hurdles. Further research will help in understanding the functions of the receptors in a “variety of physiological processes and to develop treatments for a wide range of disease conditions”. This year’s Prize once again underscores the great contributions refugees fleeing war-torn countries can make to science and other fields. Dr. Patapoutian, who is of Armenian origin, grew up in Lebanon during the country’s prolonged civil war and fled to the U.S. in 1986 as an 18-year-old. From being blissfully unaware about science as a career in Lebanon, he not only “fell in love doing basic research”, but has also excelled in it to produce path-breaking discoveries in medicine.