Nav: Home

Key regulatory role for mysterious olfaction molecule OMP

March 31, 2016

PHILADELPHIA (March 31, 2016) - New research from the Monell Center reveals that olfactory marker protein (OMP), a molecule found in the cells that detect odor molecules, plays a key role in regulating the speed and transmission of odor information to the brain. The findings solve a 30-year-old mystery regarding the function of OMP and increases understanding of how the olfactory system integrates information to transmit accurate data about odors and the messages they contain.

"At any one time, thousands of different odor molecules arrive at the smell receptors in our noses to provide detailed information about the surrounding world. OMP helps the smell receptor cells filter this vast amount of information so that animals can respond appropriately," said Monell cellular physiologist Johannes Reisert, PhD, the study's senior author.

The sensory cells that detect odors and transmit this information to the brain are nerve cells known as olfactory receptor neurons (ORNs). Each ORN contains one specific type of olfactory receptor (OR) that determines which kind of odor molecule can activate the ORN. Humans have approximately 400 different types of ORs while mice have about 1000.

The number of odor molecules arriving in the nose at any one time is influenced both by a given odor's strength (concentration) and by how frequently the animal breathes, or sniffs the air. The ORNs interpret and integrate the repetitively arriving information from odor molecules to send electrical signals called action potentials to the brain. The overall number of action potentials and the rate at which they are fired tells the brain that an odor is present and how strong that odor is.

The process of converting the chemical information from an odor molecule into an electrical signal is mediated by a complex sequence of molecular events within the ORN called olfactory transduction. Scientists knew that OMP has a role in this process, but the exact nature of this role was unclear.

In the current study, published as a featured article in the Journal of Neuroscience, the Monell researchers used mice engineered to be missing OMP, called OMP knockout mice, to identify how OMP controls the ORNs' responses to odors.

The findings revealed that OMP regulates odor processing by filtering 'noisy' signals so that incoming odor information is transmitted accurately.

When an odor is detected, the levels of a key molecule inside the ORN need to rise to a critical threshold before the ORN can fire an action potential. This molecule, called cyclic AMP (cAMP), then needs to return to baseline levels before the ORN can send another signal.

Reisert previously had found that each type of OR dictates a specific baseline level of cAMP activity in the related ORN. In the current study, the Monell scientists combined pharmacological and electrophysiological techniques to investigate OMP's role in setting these different levels of cAMP.

The results revealed that ORNs from the OMP knockout mice had similar high levels of cAMP independent of which OR was expressed. This contrasted with the varied cAMP levels observed in ORNs from normal mice.

"What this tells us is that OMP dampens cAMP 'noise' to allow the olfactory system to differentiate between ORs and to allow faithful transmission of odor information to the brain," said Reisert.

Other findings revealed that ORNs from the OMP knockout mice were less able to integrate odor information over time, and specifically were less responsive to odors present for shorter amounts of time.

"Mice normally sniff 10 times every second, so need to be able to integrate odor information arriving in short intervals or they will miss valuable odor information. OMP speeds up the transduction process so that more signals can contribute to generating action potentials," said Reisert.

Other experiments with the knockout mice revealed that OMP also contributes to the ORNs' ability to identify differences in odor concentration.

Together, the findings demonstrate that OMP plays a central role in regulating several aspects of ORN function.

"Understanding how OMP and the ORs dictate ORN responses will help drive the direction of future studies to understand how ORNs contribute to our ability to experience and respond to our olfactory world," said Monell neuroscientist Michele Dibattista, PhD, the paper's lead author.
-end-
Research reported in the publication was supported by grants from the National Institute on Deafness and Other Communication Disorders (DC009613, G20OD020296, and 1P30DC011735-01). The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. Dibattista currently is at the University of Bari in Italy.

The Monell Chemical Senses Center is an independent nonprofit basic research institute based in Philadelphia, Pennsylvania. For over 47 years, Monell has advanced scientific understanding of the mechanisms and functions of taste and smell to benefit human health and well-being. Using an interdisciplinary approach, scientists collaborate in the programmatic areas of sensation and perception; neuroscience and molecular biology; environmental and occupational health; nutrition and appetite; health and well-being; development, aging and regeneration; and chemical ecology and communication. For more information about Monell, visit http://www.monell.org.

Monell Chemical Senses Center

Related Brain Articles:

Transplanting human nerve cells into a mouse brain reveals how they wire into brain circuits
A team of researchers led by Pierre Vanderhaeghen and Vincent Bonin (VIB-KU Leuven, Université libre de Bruxelles and NERF) showed how human nerve cells can develop at their own pace, and form highly precise connections with the surrounding mouse brain cells.
Brain scans reveal how the human brain compensates when one hemisphere is removed
Researchers studying six adults who had one of their brain hemispheres removed during childhood to reduce epileptic seizures found that the remaining half of the brain formed unusually strong connections between different functional brain networks, which potentially help the body to function as if the brain were intact.
Alcohol byproduct contributes to brain chemistry changes in specific brain regions
Study of mouse models provides clear implications for new targets to treat alcohol use disorder and fetal alcohol syndrome.
Scientists predict the areas of the brain to stimulate transitions between different brain states
Using a computer model of the brain, Gustavo Deco, director of the Center for Brain and Cognition, and Josephine Cruzat, a member of his team, together with a group of international collaborators, have developed an innovative method published in Proceedings of the National Academy of Sciences on Sept.
BRAIN Initiative tool may transform how scientists study brain structure and function
Researchers have developed a high-tech support system that can keep a large mammalian brain from rapidly decomposing in the hours after death, enabling study of certain molecular and cellular functions.
Wiring diagram of the brain provides a clearer picture of brain scan data
In a study published today in the journal BRAIN, neuroscientists led by Michael D.
Blue Brain Project releases first-ever digital 3D brain cell atlas
The Blue Brain Cell Atlas is like ''going from hand-drawn maps to Google Earth'' -- providing previously unavailable information on major cell types, numbers and positions in all 737 brain regions.
Landmark study reveals no benefit to costly and risky brain cooling after brain injury
A landmark study, led by Monash University researchers, has definitively found that the practice of cooling the body and brain in patients who have recently received a severe traumatic brain injury, has no impact on the patient's long-term outcome.
Brain cells called astrocytes have unexpected role in brain 'plasticity'
Researchers from the Salk Institute have shown that astrocytes -- long-overlooked supportive cells in the brain -- help to enable the brain's plasticity, a new role for astrocytes that was not previously known.
Largest brain study of 62,454 scans identifies drivers of brain aging
In the largest known brain imaging study, scientists from Amen Clinics (Costa Mesa, CA), Google, John's Hopkins University, University of California, Los Angeles and the University of California, San Francisco evaluated 62,454 brain SPECT (single photon emission computed tomography) scans of more than 30,000 individuals from 9 months old to 105 years of age to investigate factors that accelerate brain aging.
More Brain News and Brain Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Listen Again: Reinvention
Change is hard, but it's also an opportunity to discover and reimagine what you thought you knew. From our economy, to music, to even ourselves–this hour TED speakers explore the power of reinvention. Guests include OK Go lead singer Damian Kulash Jr., former college gymnastics coach Valorie Kondos Field, Stockton Mayor Michael Tubbs, and entrepreneur Nick Hanauer.
Now Playing: Science for the People

#562 Superbug to Bedside
By now we're all good and scared about antibiotic resistance, one of the many things coming to get us all. But there's good news, sort of. News antibiotics are coming out! How do they get tested? What does that kind of a trial look like and how does it happen? Host Bethany Brookeshire talks with Matt McCarthy, author of "Superbugs: The Race to Stop an Epidemic", about the ins and outs of testing a new antibiotic in the hospital.
Now Playing: Radiolab

Dispatch 6: Strange Times
Covid has disrupted the most basic routines of our days and nights. But in the middle of a conversation about how to fight the virus, we find a place impervious to the stalled plans and frenetic demands of the outside world. It's a very different kind of front line, where urgent work means moving slow, and time is marked out in tiny pre-planned steps. Then, on a walk through the woods, we consider how the tempo of our lives affects our minds and discover how the beats of biology shape our bodies. This episode was produced with help from Molly Webster and Tracie Hunte. Support Radiolab today at Radiolab.org/donate.