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Updated: Jun 5, 2026

Ratiometric Calcium Imaging of Individual Neurons in Behaving Caenorhabditis Elegans
Published on: February 7, 2018
Receptor-type guanylate cyclase is required for carbon dioxide sensation by Caenorhabditis elegans
Elissa A Hallem1, W Clay Spencer, Rebecca D McWhirter
1Howard Hughes Medical Institute, Division of Biology, California Institute of Technology, Pasadena, CA 91125, USA.
Abstract:
CO(2) is both a critical regulator of animal physiology and an important sensory cue for many animals for host detection, food location, and mate finding. The free-living soil nematode Caenorhabditis elegans shows CO(2) avoidance behavior, which requires a pair of ciliated sensory neurons, the BAG neurons. Using in vivo calcium imaging, we show that CO(2) specifically activates the BAG neurons and that the CO(2)-sensing function of BAG neurons requires TAX-2/TAX-4 cyclic nucleotide-gated ion channels and the receptor-type guanylate cyclase GCY-9. Our results delineate a molecular pathway for CO(2) sensing and suggest that activation of a receptor-type guanylate cyclase is an evolutionarily conserved mechanism by which animals detect environmental CO(2).
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