Featured Research

from universities, journals, and other organizations

Researchers Find Biological Clock For Smell In Mice

Date:
December 19, 2006
Source:
Washington University in St. Louis
Summary:
Biologists at Washington University in St. Louis have discovered a large biological clock in the smelling center of mice brains and have revealed that the sense of smell for mice is stronger at night, peaking in evening hours and waning during day light hours. A team led by Erik Herzog, Ph.D., of Washington University, discovered the clock in the olfactory bulb, the brain center that aids the mouse in detecting odors.

A team led by Erik Herzog (shown in laboratory) has discovered a large biological clock in the smelling center of mice brains and has shown that the sense of smell for mice is stronger at night, peaking in evening hours and waning during day light hours.
Credit: Photo by David Kilper / WUSTL Photo

Biologists at Washington University in St. Louis have discovered a large biological clock in the smelling center of mice brains and have revealed that the sense of smell for mice is stronger at night, peaking in evening hours and waning during day light hours.

Related Articles


A team led by Erik Herzog, Ph.D., Washington University associate professor of Biology in Arts & Sciences, discovered the clock in the olfactory bulb, the brain center that aids the mouse in detecting odors.

The olfaction biological clock is hundreds of times larger than the known biological clock called the suprachiasmatic nucleus (SCN), located at the base of the brain right on top of where the optic nerves cross each other. Cells in both the SCN and the olfactory bulb keep 24-hour time and are normally highly sychronized to each other and environmental cycles of day-night.

"It's been a question for some time whether the SCN functions as the only biological clock," said Herzog. "One wouldn't think that the ability to smell would cycle, but that's what we show.

" I think now that the SCN is like the atomic clock, important for keeping central time, and then there are all of these peripheral clocks - for timing tasks like sleep-wake, vigilance, digestion, olfaction, hearing, touch and vision, though not all yet found. It may be that the peripheral clocks are like individual wristwatches that we must periodically reset."

Perhaps most surprising is the observation that the olfactory bulb clock can run independent of daily rhythms in sleep-wake or the SCN, making it the Big Ben of the mammalian circadian rhythm world.

"It seems to be one of those biological clocks that can keep running itself for a long time, even without the SCN," Herzog said.

Results were published in the Nov. 22, 2006, issue of the Journal of Neuroscience.

Herzog and collaborators Daniel Granados-Fuentes, Ph.D., Washington University postdoctoral researcher, and undergraduate student researcher Alan Tseng, put a little cedar oil on a Q-tip and allowed mice to sniff it for five minutes.

"We then preserved their brains and counted the number of olfactory bulb cells that had been activated by the odorant," Herzog said. "The gene cFOS is a marker for cells that were activated by the stimulus. We recorded the expression of that gene. All of the data came from in vivo measurements."

They saw more of those cells light up in the olfactory bulb at night than in the day.

"The olfactory bulb might be more sensitive at night when the creatures are active than when they are resting in the day," Herzog speculated. "This might help them find food or mates when they are hungry for food or for love."

Do the results suggest that women should splash on the Estee Lauder during the night so that men can notice all the more and shun the bottle during the day?

"There are anecdotes in the literature about humans liking certain perfumes more during the evening than the morning, and there is some evidence that we also have daily rhythms in olfaction," Herzog said.

Herzog said that it is rare to find someone missing their SCN, so it's tricky to study the human olfactory clock by itself. For this reason, his lab plans to study olfactory behavior in mice.

"We can say that this (olfactory bulb) clock has a functional consequence, and now we're setting up to do olfactory behavior," he said. "We'll ask the mice to tell us when they can smell odors of different concentrations, and we hope to learn more about how and how much the clock modulates their sense of smell, and which cells and genes are needed."

The olfactory bulb biological clock study opens up many questions, a key one of which is: Why are there multiple clocks?

"This idea of multiple biological clocks is new," Herzog said. "We might need now to consider ourselves a clock shop. It appears that disrupting the coordination between these clocks is bad for our health, like in jet lag or shift work."


Story Source:

The above story is based on materials provided by Washington University in St. Louis. Note: Materials may be edited for content and length.


Cite This Page:

Washington University in St. Louis. "Researchers Find Biological Clock For Smell In Mice." ScienceDaily. ScienceDaily, 19 December 2006. <www.sciencedaily.com/releases/2006/12/061219095350.htm>.
Washington University in St. Louis. (2006, December 19). Researchers Find Biological Clock For Smell In Mice. ScienceDaily. Retrieved October 25, 2014 from www.sciencedaily.com/releases/2006/12/061219095350.htm
Washington University in St. Louis. "Researchers Find Biological Clock For Smell In Mice." ScienceDaily. www.sciencedaily.com/releases/2006/12/061219095350.htm (accessed October 25, 2014).

Share This



More Plants & Animals News

Saturday, October 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Deep Sea 'mushroom' Could Be Early Branch on Tree of Life

Deep Sea 'mushroom' Could Be Early Branch on Tree of Life

Reuters - Innovations Video Online (Oct. 24, 2014) Miniature deep sea animals discovered off the Australian coast almost three decades ago are puzzling scientists, who say the organisms have proved impossible to categorise. Academics at the Natural History of Denmark have appealed to the world scientific community for help, saying that further information on Dendrogramma enigmatica and Dendrogramma discoides could answer key evolutionary questions. Jim Drury has more. Video provided by Reuters
Powered by NewsLook.com
Black Bear Cub Goes Sunday Shopping

Black Bear Cub Goes Sunday Shopping

Reuters - Light News Video Online (Oct. 23, 2014) Price check on honey? Bear cub startles Oregon drugstore shoppers. Rough Cut (no reporter narration). Video provided by Reuters
Powered by NewsLook.com
Dances With Wolves in China's Wild West

Dances With Wolves in China's Wild West

AFP (Oct. 23, 2014) One man is on a mission to boost the population of wolves in China's violence-wracked far west. The animal - symbol of the Uighur minority there - is under threat with a massive human resettlement program in the region. Duration: 00:41 Video provided by AFP
Powered by NewsLook.com
Breakfast Debate: To Eat Or Not To Eat?

Breakfast Debate: To Eat Or Not To Eat?

Newsy (Oct. 23, 2014) Conflicting studies published in the same week re-ignited the debate over whether we should be eating breakfast. Video provided by Newsy
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


Plants & Animals

Earth & Climate

Fossils & Ruins

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