Fig. 5. Dose–response curves for halothane of N2 and gas-1 grown under different concentrations of oxygen. Nematodes were grown in 3%, 21% (room air), and 60% oxygen, and the dose–response curves in halothane were determined for young adult animals. Gas-1 animals did not survive exposure to 60% oxygen. The results show that hypoxia moves the gas-1 response to the right (EC50=2.0%), whereas hyperoxia moves the response of N2 to the left (EC50=2.2%).