Mice use specialized neurons to detect carbon dioxide in the air

Danh Phuong

For rats, carbon dioxide means danger. The new study from Rockefeller University proves that mice have a way of identifying carbon dioxide related to a particular olfactory neuron, discovering that implies a predictable increase in carbon dioxide in Air can affect animal activity.

Carbon dioxide detector. Beams that shoot out like hairs come from the nipples at the top of the GC-D expressing neuron. New research in mice shows that GC-D expressing neurons in the olfactory epithelium are activated by the reception of carbon dioxide. Most olfactory sensory neurons exhibit odor receptor molecules and are located in the nasal cavity to sense the smell. But a small subset that expresses an enzyme called guanylyl cyclase-D (GC-D for short).

Peter Mombaerts, professor and director of the Laboratory for Neuroscience and Development Biology at Rockefeller, and Andreas Walz, a lab researcher at Mombaerts, created a mouse that contains the neurons express GC-D, glowing like fluorescent green protein lights. These GC-D expression neurons also release the nerve endings to an abnormal structure located in the back of the olfactory bulb, also known as string platelets, like a string of beads.

(Photo: Rockefeller University provided) The Rockefeller research team in China, led by Minmin Luo at the National Institute of Biological Sciences in Beijing, discovered: all GC-D expression neurons in activated olfactory epithelium are due to exposure of carbon dioxide. In contrast, all cells in the nasal cavity layer are activated by carbon dioxide, which is GC-expressing neurons.

Mombaerts said: 'These findings prove a specialized subsystem has evolved in mice to identify carbon dioxide.'

Carbon dioxide forms about 4/100 of 1/100 air. To determine the threshold for carbon dioxide recognition in mice, the Beijing team trained mice to lick water when they caught the wind that contained higher levels of carbon dioxide. When the amount of carbon dioxide in the wind is reduced, the exact reaction of the animals becomes random. Statistical analysis has set a threshold of recognition of about 6/100 of 1% of air, just above the average air level.

Mombaerts notes, scientists still do not know if the GC-D enzyme is responsible for identifying carbon dioxide. Mombaerts said: 'GC-D is a standard mark for neurons with special sensitivity to carbon dioxide.' 'Right now, we have not yet demonstrated the mechanical theory of standards involved in sensory perception of carbon dioxide. However, the study suggests that scientists need to watch for changes in activity in animals such as an increase in the level of carbon dioxide in the air, because at some point animals have perceived levels of increase, " Mombaerts said.

He added: 'Animals can adapt to the gradual and gradual increase, causing a range of change activities such as increased aggression, or impairment of fertility.'

Note: This article is adapted from a newsletter published by Rockefeller University.