I’ve written about the science behind acquired taste and cybernetic eyes. I planned to touch on the other senses. (Pun intended!) What better time to investigate the science behind touch, since two scientists have won a Nobel Prize for the discovery of touch receptors. Using seemingly random items; chili peppers and pipettes!
THE SCIENCE BEHIND TOUCH
I bet you a pizza that Dr. Patapoutian (one of the Nobel prize winners) would have voted for the sense of touch!
HOW DOES TOUCH WORK?
Touch is an elemental function of the nervous system, which is how we react with our environment!
Let’s start with a quick review of the science of touch.
What better way than with a mini guide of signaling in the human nervous system. Yes, a touch of science!
THERE WILL BE A QUICK TOUCH OF SCIENCE ALA REVIEW OF THE NERVOUS SYSTEM...I promise it's speedy quick! (yes, another pun)
A FEW TOUCH RECEPTORS TO INCLUDE HEAT, COLD, PAIN, PRESSURE, PROPRIOCEPTION (where we are in space!)
I bet you’re saying to yourself, ‘what’s the big deal with discovering sensory neurons?’ We know the touch receptors are there, especially when we step on a bee or our hot cocoa is too hot.
The big deal was that scientists didn’t know where the receptors that stimulated the sensory neurons were located, not exactly. ‘In our skin’ doesn’t cut it. Unless we get a cut. (There won’t be blood in this post either.)
Scientists had been searching for touch and temperature receptors for many years. Everyone knew they were there somewhere, but no one knew where they were.
Here’s some of what we did know before the discovery of the touch receptors!
SOME HISTORY OF THE SCIENCE BEHIND TOUCH
A post about nerves and the science of touch wouldn’t be complete without touching on pain. (pun # 3 for the win) And if you’re interested in the intrigue of poisons, which also cause pain, click here.
THE SCIENCE BEHIND TOUCH : PAIN
Maybe people don’t care to think about touch because of the negative connotations. AKA PAIN.
A-delta and C-fibers
Because of myelination & diameter differences, painful stimuli from A-delta fibers arrive in your brain before those same painful stimuli from the C-fibers. But the C-fibers place in the pain race.
How nice for us!
The A-delta fibers send the “first pain” into the brain.
C-fibers travel more slowly, so you notice the pain from C-fibers several seconds following an injury.
THE SCIENCE BEHIND TOUCH : PROPRIOCEPTION
Here’s another example of something we take for granted. Proprioception.
The sense that lets us perceive the location, movement, and action of parts of the body is proprioception or kinesthesia.
A-alpha fibers are the proprioceptive fibers and easily the fastest. Why?
Now that we’re up to A-alpha myelination knowledge speeds, let’s get to the newest discovery!
HOW DOES TOUCH WORK?
These two scientists won the 2021 Nobel Prize for Physiology or Medicine for answering the million dollar question:
How are temperature and mechanical stimuli converted into electrical impulses in the nervous system?
(It doesn’t sound as exciting when I type ‘physiology or medicine’ as if they aren’t important enough to have their own category!)
HOW DOES TOUCH WORK...ION CHANNELS
TRPV1 is an ion channel activated by painful heat.
TRPM8 is an ion channel that is activated by cold.
Piezo1 and Piezo2 are opened by mechanical force.
What does all that actually mean?
THESE NEWLY DISCOVERED RECEPTORS RESPOND TO HOT & COLD!
NOW THAT YOU KNOW ALL ABOUT THE SCIENCE OF TOUCH, WHY DOES THIS MATTER?
The identified ion channels are important for many physiological processes and disease conditions.
We’ve come a long way learning about the science behind touch since Descartes.
MORE TOUCH RECEPTORS ARE POPPING UP!
PIEZO PROTEIN ION CHANNEL APPLICATIONS
Remember that silencing the Piezo gene renders the cells insensitive to poking with a micropipette! In theory, silencing touch / proprioception could help with issues such as mechanical (joint) pain, respiration, blood pressure, and skeletal remodeling.
TPV1 PROTEIN CHANNEL APPLICATIONS
And the TPV1 channel could be closed, thus decreasing issues such as inflammatory pain, lower core body temperature due to high fevers, dampen protective reflexes or aid with neuropathies and visceral pain.
PERIPHERAL NEUROPATHY AND DIABETES
How about peripheral neuropathy and diabetes! It would be cool to do the opposite & stimulate the TPV1 channels, so people w/o sensation would notice if they stepped on a thumbtack or cut themselves. They could take care of their injuries instead of getting infections.
THE SCIENCE BEHIND TOUCH
Let’s give it up for these scientists. They identified critical missing links towards understanding how our bodies respond to the world around us.
And when they use their Nobel prize money–an equal split of $1.1 million–to host a pizza party for their lab staff, you can be sure everyone knows the mechanism when they burn their hard palates!