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Updated: Jul 18, 2026
06:53
Parallel Measurement of Circadian Clock Gene Expression and Hormone Secretion in Human Primary Cell Cultures
Published on: November 11, 2016
A circadian clock in the olfactory bulb controls olfactory responsivity.
Daniel Granados-Fuentes1, Alan Tseng, Erik D Herzog
1Department of Biology, Washington University, St. Louis, Missouri 63130-4899, USA. dgranado@biology2.wustl.edu
Summary
The main olfactory bulb (OB) acts as a master circadian pacemaker, regulating daily rhythms in olfaction and influencing other behaviors. This finding reveals a key role for the OB in coordinating the body's internal clock.
Area of Science:
- Neuroscience
- Chronobiology
- Olfactory System
Background:
- Mammalian cells exhibit daily rhythms in vitro.
- The suprachiasmatic nucleus (SCN) regulates circadian behaviors.
- The role of intrinsic tissue rhythmicity beyond the SCN is unclear.
Purpose of the Study:
- To investigate if the main olfactory bulb (OB) mediates daily changes in olfaction.
- To determine the OB's role in circadian rhythmicity.
Main Methods:
- Assessed c-Fos expression (cellular excitation marker) in response to odorants.
- Utilized SCN lesions and OB removal in mice.
- Monitored locomotor activity and light-dark cycles.
Main Results:
- Circadian rhythms of odor-induced c-Fos were observed in the OB and piriform cortex (PC), persisting after SCN lesions.
- OB removal abolished PC circadian rhythms and altered locomotor activity.
- OB manipulation affected SCN rhythm amplitude and PC rhythmicity.
Conclusions:
- The OB functions as a master circadian pacemaker.
- The OB enhances olfactory responsiveness and drives rhythms in the PC.
- The OB interacts with the SCN to coordinate daily behaviors.
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