Featured Research

from universities, journals, and other organizations

Researchers Discover Key To Body's Ability To Detect Subtle Temperature Changes

Date:
February 26, 2007
Source:
University of California, Davis - Health System
Summary:
Scientists have long known the molecular mechanisms behind most of the body's sensing capabilities. Vision, for example, is made possible in part by rhodopsin, a pigment molecule that is extremely sensitive to light. It is involved in turning photons into electrical signals that can be decoded by the brain into visual information. But how the human body is able to sense a one-degree change in temperature has remained a mystery.

Scientists have long known the molecular mechanisms behind most of the body's sensing capabilities. Vision, for example, is made possible in part by rhodopsin, a pigment molecule that is extremely sensitive to light. It is involved in turning photons into electrical signals that can be decoded by the brain into visual information. But how the human body is able to sense a one-degree change in temperature has remained a mystery.

Related Articles


"For a long time, we didn't know how temperature sensing was being carried out in animals," said Jie Zheng, assistant professor in the Department of Physiology and Membrane Biology at the UC Davis School of Medicine. Huge progress was made in the last decade, Zheng said, when scientists discovered four ion channels sensitive to heat and two cold-sensitive ones.

"But, it was still unclear how only six temperature-sensor channels could cover wide ranges of temperature and still discriminate subtle differences," Zheng said.

Using a novel method based on a technique first used by physicists, Zheng and his colleagues now have shown that the subunits of one channel can come together with subunits from another channel or coassemble in laboratory cell cultures to form new functioning channels. Assuming this process also happens in normal cells, it suggests a likely mechanism for the thermosensitivity seen in all animal cells, Zheng explained.

"We found that, by reassembling subunits we potentially have a lot more than six channel types responsible for the sensing of temperature," he said.

The current findings are featured on the cover of the March issue of the Journal of General Physiology and were published online today.

Ion channels are pore-forming proteins found in the membranes of cells. They have the ability to open and close, regulating the flow of charged ions and controlling the voltage gradient found between the inside and outside of every living cell.

In the current study, Zheng and his colleagues focused on a group of ion channels called transient receptor potential (TRP) channels. In all, there are more than 20 TRP channels. Zheng's group studied four of the six channels that have been shown to be involved in sensing temperature.

Previous studies concluded that different thermosensitive TRP channel subunits did not coassemble, Zheng said. He realized, however, that there were some technical limitations to the previous work. So, he and his colleagues decided to use a technique they developed last year, called spectra FRET. Spectra FRET, or spectroscopy-based fluorescence resonance energy transfer, allows the researcher to observe interactions between different channel subunits under a microscope.

"This technique allows us to look at the channel subunit composition in real-time in live cells," Zheng said.

In the current experiments, cDNA coding for particular subunits is linked to cDNA coding for fluorescent proteins and then added to a culture of human embryonic kidney cells. The cells take up the DNA and then express the channel proteins, each now having a fluorescent protein tag. The researchers then observed the cells in the spectra FRET apparatus.

"Using spectra FRET, we were able to focus on just the signal from the plasma membrane," Zheng explained. "What we found was that the subunits of one kind of heat-sensitive channel coassembled with subunits of other heat-sensitive channels to form new channels. This means that instead of four heat-sensitive channels we have a potential of 256 heat-sensitive channels with potentially different temperature sensitivity ranges."

Zheng and his colleagues then confirmed their results using a technique called patch clamping that allowed them to record the electrical current flowing through individual open channels.

"Using these single-molecule recordings, we see many different channel types," Zheng said. The next question we are trying to address is whether they really have different temperature sensitivity. We believe the answer is 'yes,' but we have to show that."

Zheng also believes it is likely that the channels responsible for sensing cold coassemble in the same way. The cold- and heat-sensing subunits, however, do not seem to coassemble, he said.

The findings by Zheng and his colleagues promise to help solve the mystery of temperature sensitivity in animals once and for all. And, because the cells with these ion channels in their membranes are also the cells that sense pain, the basic knowledge they have provided may one day prove useful to scientists looking for novel remedies for pain.

"We have to re-examine everything from how people acclimate to hot climates to how they respond to spicy food based on the understanding that there are many more kinds of channels involved," Zheng said.

Co-authors of the current study include visiting scientist Wei Cheng from China; graduate student Fan Yang; and former lab technician Christina L. Takanishsi. The research was supported by a grant from the American Heart Association.


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. "Researchers Discover Key To Body's Ability To Detect Subtle Temperature Changes." ScienceDaily. ScienceDaily, 26 February 2007. <www.sciencedaily.com/releases/2007/02/070226095053.htm>.
University of California, Davis - Health System. (2007, February 26). Researchers Discover Key To Body's Ability To Detect Subtle Temperature Changes. ScienceDaily. Retrieved December 22, 2014 from www.sciencedaily.com/releases/2007/02/070226095053.htm
University of California, Davis - Health System. "Researchers Discover Key To Body's Ability To Detect Subtle Temperature Changes." ScienceDaily. www.sciencedaily.com/releases/2007/02/070226095053.htm (accessed December 22, 2014).

Share This


More From ScienceDaily



More Health & Medicine News

Monday, December 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Christmas Kissing Good for Health

Christmas Kissing Good for Health

Reuters - Innovations Video Online (Dec. 22, 2014) Scientists in Amsterdam say couples transfer tens of millions of microbes when they kiss, encouraging healthy exposure to bacteria. Suzannah Butcher reports. Video provided by Reuters
Powered by NewsLook.com
Brain-Dwelling Tapeworm Reveals Genetic Secrets

Brain-Dwelling Tapeworm Reveals Genetic Secrets

Reuters - Innovations Video Online (Dec. 22, 2014) Cambridge scientists have unravelled the genetic code of a rare tapeworm that lived inside a patient's brain for at least four year. Researchers hope it will present new opportunities to diagnose and treat this invasive parasite. Matthew Stock reports. Video provided by Reuters
Powered by NewsLook.com
Touch-Free Smart Phone Empowers Mobility-Impaired

Touch-Free Smart Phone Empowers Mobility-Impaired

Reuters - Innovations Video Online (Dec. 21, 2014) A touch-free phone developed in Israel enables the mobility-impaired to operate smart phones with just a movement of the head. Suzannah Butcher reports. Video provided by Reuters
Powered by NewsLook.com
Earthworms Provide Cancer-Fighting Bacteria

Earthworms Provide Cancer-Fighting Bacteria

Reuters - Innovations Video Online (Dec. 21, 2014) Polish scientists isolate bacteria from earthworm intestines which they say may be used in antibiotics and cancer treatments. Suzannah Butcher reports. Video provided by Reuters
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