Featured Research

from universities, journals, and other organizations

How the body senses a range of hot temperatures

Date:
March 2, 2012
Source:
University of California - Davis Health System
Summary:
The winter sun feels welcome, but not so a summer sunburn. Research over the past 20 years has shown that proteins on the surface of nerve cells enable the body to sense several different temperatures.

The winter sun feels welcome, but not so a summer sunburn. Research over the past 20 years has shown that proteins on the surface of nerve cells enable the body to sense several different temperatures. Now scientists have discovered how just a few of these proteins, called ion channels, distinguish perhaps dozens of discrete temperatures, from mildly warm to very hot.

Related Articles


Researchers showed that the building blocks, or subunits, of heat-sensitive ion channels can assemble in many different combinations, yielding new types of channels, each capable of detecting a different temperature. The discovery, in cell cultures, demonstrates for the first time that only four genes, each encoding one subunit type, can generate dozens of different heat-sensitive channels.

"Researchers in the past have assumed that because there are only four genes, there are only four heat-sensitive channels, but now we have shown that there are many more," said Jie Zheng, leader of the research and an associate professor of physiology and membrane biology at the UC Davis School of Medicine.

The research was published in the Journal of Biological Chemistry on March 2.

Ion channels are pores in cell membranes. Their ability to open and close controls the flow of charged ions, which turns neuron signalling on or off -- in this case to inform the body of the temperature the neuron senses.

The researchers found that when different subunits combine, the resultant hybrid, or heteromeric, channel can detect temperatures about midway between what the "parent" channels detect.

One of the channels they studied, called TRPV1, reacts to hot temperatures -- about 100 degrees Fahrenheit. It is also responsible for the ability to sense spicy foods, such as chili peppers. A second channel, TRPV3, responds to temperatures of about 85 degrees. It also senses many food flavors such as those found in rosemary, oregano, vanilla and cinnamon that elicit a warm sensation.

When the TRPV1 and TRPV3 subunits recombine, the heteromeric channel is tuned to about 92 degrees. Surprisingly, the study showed that the hybrid channel has an even higher chemical sensitivity than the channels that made it up.

Zheng and his colleagues also showed that channels made up of TRPV1 and TRPV3 subunits react to heat at a rate about midway between that of the two constituent channel subunits. But repeatedly exposing the hybrid channels to their target temperature boosted their response, a behavior called sensitization, which TRPV3 also exhibits.

"It says 'I remember this temperature. I will make a really loud noise to tell the system that it is coming,'" Zheng said. The process allows the body to be more sensitive to temperature.

By contrast, TRPV1 typically responds the same way when repeatedly exposed to its target temperature -- and sometimes even decreases its response, a process called desensitization. It helps the body to adapt to high temperature, Zheng explained.

The research builds on work the team published in 2007 demonstrating that the heat-sensitive subunits can combine to form heteromeric channels. However, at the time, scientists didn't know how these channels respond to heat. The new work shows that the channels are indeed sensitive to different temperatures.

"Knowing that there are many distinct heat-sensing ion channels now opens the way to understand how neurons encode precise temperature information, an important process that allows us to enjoy the rich spectrum of temperature in life -- a memorable warm handshake, a soothing shower and a cup of hot latte -- and add vanilla flavor, please," Zheng said. "It also may provide insights regarding the causes and potential treatments for temperature-sensitivity disorders, such as Raynaud's syndrome."

Raynaud's syndrome is a condition that causes some areas of the body -- such as fingers, toes, the tip of the nose and ears -- to feel numb and cool in response to cold temperatures or stress. The cause is unknown.

The scientists introduced the genes for TRPV1 and TRPV3 channel subunits to cultured human kidney cells. They tagged the genes with fluorescent markers to confirm when the resulting proteins had combined to form a new channel complex.

Once functional channels were formed, the researchers used a glass pipette with a very fine tip to record ion channels' responses to temperature changes.

In order to rapidly increase the temperature, they built an apparatus that allowed them to deliver an infrared laser beam to the cell. The method allowed them to heat the channel more than a thousand times faster than commercially available heating devices.

The collaborative research is funded by the National Institutes of Health, the American Heart Association and the Chinese government.


Story Source:

The above story is based on materials provided by University of California - Davis Health System. Note: Materials may be edited for content and length.


Cite This Page:

University of California - Davis Health System. "How the body senses a range of hot temperatures." ScienceDaily. ScienceDaily, 2 March 2012. <www.sciencedaily.com/releases/2012/03/120302083222.htm>.
University of California - Davis Health System. (2012, March 2). How the body senses a range of hot temperatures. ScienceDaily. Retrieved November 20, 2014 from www.sciencedaily.com/releases/2012/03/120302083222.htm
University of California - Davis Health System. "How the body senses a range of hot temperatures." ScienceDaily. www.sciencedaily.com/releases/2012/03/120302083222.htm (accessed November 20, 2014).

Share This


More From ScienceDaily



More Health & Medicine News

Thursday, November 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

UN Says It Will Scale Up Its Ebola Response

UN Says It Will Scale Up Its Ebola Response

AFP (Nov. 20, 2014) UN Resident Coordinator David McLachlan-Karr and WHO representative in the country Daniel Kertesz updated the media on the UN Ebola response on Wednesday. Duration: 00:51 Video provided by AFP
Powered by NewsLook.com
Takata Offers "sincerest Condolences" To Victims of Malfunctioning Airbag

Takata Offers "sincerest Condolences" To Victims of Malfunctioning Airbag

Reuters - US Online Video (Nov. 20, 2014) U.S. Congress hears from a victim and company officials as it holds a hearing on the safety of Takata airbags after reports of injuries. Rough Cut (no reporter narration). Video provided by Reuters
Powered by NewsLook.com
Obesity Costs Almost As Much As War And Terrorism

Obesity Costs Almost As Much As War And Terrorism

Newsy (Nov. 20, 2014) The newest estimate of the cost of obesity is pretty jarring — $2 trillion. But how did researchers get to that number? Video provided by Newsy
Powered by NewsLook.com
Ebola Crisis Affecting US Adoptions

Ebola Crisis Affecting US Adoptions

AP (Nov. 20, 2014) The Sanborn family had hoped they'd be able to bring home their 5-year-old adopted son from Liberia by now. But Ebola has forced them to wait. The boy is just one of thousands of orphans in West Africa who've been impacted by the deadly virus. (Nov. 20) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins