A Sensor for Low Environmental Oxygen in the Mouse Main Olfactory Epithelium

Area of Science:

• Physiology
• Neuroscience
• Sensory Biology

Background:

• Oxygen sensing is crucial for survival across organisms.
• Mammalian olfactory systems have not been previously linked to oxygen detection.
• The mechanisms of environmental oxygen sensing in mammals remain largely unexplored.

Purpose of the Study:

• To investigate the role of the mammalian olfactory system in sensing environmental oxygen levels.
• To identify the molecular components involved in oxygen-mediated olfactory responses.
• To determine the physiological and behavioral consequences of environmental oxygen sensing via the olfactory system.

Main Methods:

• Utilized calcium imaging in mouse main olfactory epithelium.
• Employed genetic knockout models for Gucy1b2 and Trpc2.
• Performed in vivo electrophysiology in the olfactory bulb.
• Assessed conditioned place aversion in response to low oxygen.

Main Results:

• Demonstrated direct activation of specific olfactory sensory neurons by low environmental oxygen.
• Identified Gucy1b2 and Trpc2 as essential for oxygen-induced calcium influx in these neurons.
• Showed Gucy1b2-dependent activation of olfactory bulb neurons in response to low oxygen.
• Confirmed the requirement of Gucy1b2 and Trpc2 for conditioned place aversion induced by hypoxia.

Conclusions:

• The mammalian main olfactory epithelium possesses a chemosensory function for detecting environmental oxygen.
• Soluble guanylate cyclase Gucy1b2 and cation channel Trpc2 are critical molecular players in this oxygen-sensing pathway.
• This olfactory-based oxygen sensing likely enables rapid environmental oxygen assessment and influences behavior.