title: Temperature, oxygen, and salt-sensing neurons in C. elegans are carbon dioxide sensors that control avoidance behavior.
abstract: Homeostatic control of body fluid CO(2) is essential in animals but is poorly understood. C. elegans relies on diffusion for gas exchange and avoids environments with elevated CO(2). We show that C. elegans temperature, O(2), and salt-sensing neurons are also CO(2) sensors mediating CO(2) avoidance. AFD thermosensors respond to increasing CO(2) by a fall and then rise in Ca(2+) and show a Ca(2+) spike when CO(2) decreases. BAG O(2) sensors and ASE salt sensors are both activated by CO(2) and remain tonically active while high CO(2) persists. CO(2)-evoked Ca(2+) responses in AFD and BAG neurons require cGMP-gated ion channels. Atypical soluble guanylate cyclases mediating O(2) responses also contribute to BAG CO(2) responses. AFD and BAG neurons together stimulate turning when CO(2) rises and inhibit turning when CO(2) falls. Our results show that C. elegans senses CO(2) using functionally diverse sensory neurons acting homeostatically to minimize exposure to elevated CO(2).
authors: MRC Laboratory of Molecular Biology, Hills Road, Cambridge CB2 0QH, UK.
authors: Andrew Jonathan
authors: AJ
authors: Bretscher
authors: Eiji
authors: E
authors: Kodama-Namba
authors: Karl Emanuel
authors: KE
authors: Busch
authors: Robin Joseph
authors: RJ
authors: Murphy
authors: Zoltan
authors: Z
authors: Soltesz
authors: Patrick
authors: P
authors: Laurent
authors: Mario
authors: M
authors: de Bono
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000502:physiology*; D017173:Caenorhabditis elegans; D002118:Calcium / Q000378:metabolism; D002245:Carbon Dioxide; D006706:Homeostasis / Q000502:physiology*; D015640:Ion Channel Gating / Q000502:physiology; D009043:Motor Activity / Q000502:physiology; D010100:Oxygen; D011984:Sensory Receptor Cells / Q000502:physiology*; D012965:Sodium Chloride
chemical_list: D002245:Carbon Dioxide; D012965:Sodium Chloride; D010100:Oxygen; D002118:Calcium