උණුසුම් පුවතක්
2021 වෛද්ය විද්යාව / භෞතවේදය පිළිබඳ නොබෙල් තැග්ග උණුසුම (තාපය) අපට දැනෙන්නේ කෙසේ දැයි විස්තර කළ දෙදෙනකුට හිමි වී තිබෙනවා. ඒ පිළිබඳ ව පළ වු පුවතක් පහත පළවෙනවා. නොබෙල් කමිටුවට ගිනි පෑගූ භෞතවේද මහාචාර්ය කාලෝ අමතක වී ද? මිය ගිය අයට තෑග්ග නොදීම එයට හේතුව වුණා ද දන්නෙ නැහැ. කොවිඩ් සම්බන්ධයෙන් නොබෙල් තෑග්ග කවදා හරි මෙරට ප්රාමාණික විශේෂඥයකුට ලැබේවි ද?
The 2021 Nobel prize for
physiology or medicine has been awarded to David Julius and Ardem Patapoutian
for discovering how cells detect temperature and touch.
“This really unlocks one of
the secrets of nature,” said the secretary of the Nobel committee, Thomas
Perlmann. “It explains at a molecular level how these stimuli can be converted
into nerve signals. It is something that is crucial for our survival.”
The ability to sense heat and mechanical pressure is vital for
everything from avoiding getting burned to knowing when we need to urinate, but
until recently we didn’t know exactly how nerve cells detect heat and touch.
To discover how nerve cells
detect heat, David Julius at the University of California, San Francisco,
exploited the fact that capsaicin in chillies activates heat receptors. In the
1990s, his team took the DNA of genes known to be active in sensory cells and
added fragments to cells that don’t normally respond to capsaicin.
By trying out thousands of
different fragments to see which enabled the cells to make the receptor and
respond to capsaicin, they identified a protein now called TRPV1 that codes for an
ion channel that sits in the cell membrane of nerves. Higher temperatures open
the ion channel, leading to a change in voltage that makes the nerve fire and
thus provides the sensation of heat.
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Teams led by Julius and
Ardem Patapoutian, at Scripps Research in La Jolla, California, then
independently discovered a similar ion channel called TRPM8 that opens in
response to cold rather than heat. Both teams exploited the fact that menthol triggers these cold receptors. Several similar ion
channels have since been discovered, allowing a range of different temperatures
to be sensed.
To identify touch
receptors, Patapoutian’s team used cells that produce an electrical signal when
poked. The team also identified 270 genes that might code for touch receptor
proteins. The researchers switched off these genes in the cells one by one.
In this way, they found
PIEZO1, an ion channel that opens in response to mechanical pressure. That
enabled them to identify a similar protein called PIEZO2. These receptors
help the body detect things such as blood pressure, bladder
pressure and breathing in addition to external touches.
Perlmann said he spoke
briefly to Julius and Patapoutian before the announcement. “I only had a few
minutes to talk to them but they were incredibly happy and as far as I could
tell they were very surprised and little bit shocked maybe,” he said.
