Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Electric Signals Amplify Weak Olfactory Stimuli in the Nose

01.02.2011
Scientists at Heidelberg University decipher functioning of olfactory cells

The human olfactory system possesses a special electric amplification mechanism that enables olfactory cells to respond even to extremely weak stimuli.

Scientists at Heidelberg University headed by physiologist Prof. Dr. Stephan Frings have now established how this mechanism works. Crucial is the role played by chloride ions stored in the sensory cilia of the nose. As soon as the olfactory receptors in the sensory cilia detect odorants, the chloride ions are immediately discharged. This process generates strong electric signals that pass on the relevant olfactory information to the brain.

Our noses detect a huge variety of odorants in the air we breathe. The olfactory system is confronted with an immense diversity of chemical compounds. The air in a room where a coffee machine is making coffee, where there are plants on the window-sill and people walking in and out contains thousands of different odorants. But our olfactory system finds this apparent chaos easy to deal with. It unerringly identifies the smell of coffee, although that smell alone is made up of over 800 different odorants. For this purpose the olfactory cells in the nose are equipped with olfactory receptors, proteins presented to the inhaled air on fine sensory cilia by the olfactory cells.

Up to now, research on olfactory cells and their receptors has been dogged by one unanswered question. The concentration of individual odorants in the nose – i.e. the number of molecules of a given odorant per cubic centimetre of ambient air – is very low. In addition, olfactory receptors have proved to be relatively insensitive, only responding very weakly to low odorant concentrations. So how can the key function of our highly sensitive olfactory system be performed by receptors that are themselves remarkably insensitive? The answer lies in the electric amplification mechanism for the olfactory cells deciphered by Prof. Frings and his team at Heidelberg University’s Centre for Organismal Studies.

The sensory cilia of the olfactory cells prepare themselves for the job in a special way. A protein complex pumps chloride ions into the interior of the sensory cilia, thus making them into well-filled chloride stores. When an olfactory stimulus occurs, another protein swings into action, a chloride channel that the sensory cilia possess many copies of in their external membranes. These chloride channels remain closed as long as the olfactory cell is at rest. When an olfactory stimulus is registered, the weak response of the olfactory receptors immediately opens all the channels. The release of negatively charged chloride ions causes a loading inversion in the olfactory cell. This in its turn produces strong electric signals that are conveyed to the brain with the olfactory information.

For more information, go to http://www.molekulare-physiologie.de/index_en.html.

Original publication:
T. Hengl, H. Kaneko, K. Dauner, K. Vocke, S. Frings, F. Möhrlen: Molecular Components of Signal Amplification in Olfactory Sensory Cilia. PNAS (30 March 2010) 107:6052-6057, doi: 10.1073/pnas.0909032107
Contact:
Prof. Dr. Stephan Frings
Centre for Organismal Studies
Department of Molecular Animal Physiology
phone: +49 6221 545661
s.frings@zoo.uni-heidelberg.de
Communications and Marketing
Press Office, phon +49 6221 543211
presse@reaktorat.uni-heidelberg.de

Marietta Fuhrmann-Koch | idw
Further information:
http://www.uni-heidelberg.de
http://www.molekulare-physiologie.de/index_en.html

More articles from Life Sciences:

nachricht Topologische Quantenchemie
21.07.2017 | Max-Planck-Institut für Chemische Physik fester Stoffe

nachricht Topological Quantum Chemistry
21.07.2017 | Max-Planck-Institut für Chemische Physik fester Stoffe

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Manipulating Electron Spins Without Loss of Information

Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.

For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...

Im Focus: The proton precisely weighted

What is the mass of a proton? Scientists from Germany and Japan successfully did an important step towards the most exact knowledge of this fundamental constant. By means of precision measurements on a single proton, they could improve the precision by a factor of three and also correct the existing value.

To determine the mass of a single proton still more accurate – a group of physicists led by Klaus Blaum and Sven Sturm of the Max Planck Institute for Nuclear...

Im Focus: On the way to a biological alternative

A bacterial enzyme enables reactions that open up alternatives to key industrial chemical processes

The research team of Prof. Dr. Oliver Einsle at the University of Freiburg's Institute of Biochemistry has long been exploring the functioning of nitrogenase....

Im Focus: The 1 trillion tonne iceberg

Larsen C Ice Shelf rift finally breaks through

A one trillion tonne iceberg - one of the biggest ever recorded -- has calved away from the Larsen C Ice Shelf in Antarctica, after a rift in the ice,...

Im Focus: Laser-cooled ions contribute to better understanding of friction

Physics supports biology: Researchers from PTB have developed a model system to investigate friction phenomena with atomic precision

Friction: what you want from car brakes, otherwise rather a nuisance. In any case, it is useful to know as precisely as possible how friction phenomena arise –...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Closing the Sustainability Circle: Protection of Food with Biobased Materials

21.07.2017 | Event News

»We are bringing Additive Manufacturing to SMEs«

19.07.2017 | Event News

The technology with a feel for feelings

12.07.2017 | Event News

 
Latest News

NASA looks to solar eclipse to help understand Earth's energy system

21.07.2017 | Earth Sciences

Stanford researchers develop a new type of soft, growing robot

21.07.2017 | Power and Electrical Engineering

Vortex photons from electrons in circular motion

21.07.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>