From UPSC perspective, the following things are important :
Prelims level : Nobel Price, Genes controling senses
Mains level : Read the attached story
U.S. scientists David Julius and Ardem Patapoutian have won the Nobel Medicine Prize for discoveries on receptors for temperature and touch.
Who are the Laureates?
- David Julius and Ardem Patapoutian, working independently in the United States, made a series of discoveries in the late 1990s and early 2000s.
- They figured out the touch detectors in our body and the mechanism through which they communicate with the nervous system to identify and respond to a particular touch.
What did they discover?
- They discovered the molecular sensors in the human body that are sensitive to heat, and to mechanical pressure, and make us “feel” hot or cold, or the touch of a sharp object on our skin.
- n 1997, Dr. Julius and his team published a paper in Nature detailing how capsaicin, or the chemical compound in chili peppers, causes the burning sensation.
- They created a library of DNA fragments to understand the corresponding genes and finally discovered a new capsaicin receptor and named it TRPV1.
- This discovery paved the way for the identification of many other temperature-sensing receptors.
- They identified another new receptor called TRPM8, a receptor that is activated by cold. It is specifically expressed in a subset of pain-and-temperature-sensing neurons.
- They identified a single gene PIEZO2, which when silenced made the cells insensitive to the poking. They named this new mechanosensitive ion channel Piezo1.
How do they work?
- The human ability to sense heat or cold and pressure is not very different from the working of the many detectors that we are familiar with.
- When something hot, or cold, touches the body, the heat receptors enable the passage of some specific chemicals, like calcium ions, through the membrane of nerve cells.
- It’s like a gate that opens up on a very specific request. The entry of the chemical inside the cell causes a small change in electrical voltage, which is picked up by the nervous system.
- There is a whole spectrum of receptors that are sensitive to different ranges of temperature.
- When there is more heat, more channels open up to allow the flow of ions, and the brain is able to perceive higher temperatures.
- Breakthroughs in physiology have often resulted in an improvement in the ability to fight diseases and disorders. This one is no different.
- There are receptors that make us feel pain. If these receptors can suppress, or made less effective, the person had felt less pain.
- Chronic pain is present is a number of illnesses and disorders. Earlier, the experience of pain was a mystery.
- But as we understand these receptors more and more, it is possible that we gain the ability to regulate them in such a way that the pain is minimized.
[Note: We will compile all Nobel Prizes into a single post once all are awarded.]