Oxygen regulation of breathing through an olfactory receptor activated by lactate.

The G-protein-coupled receptor olfactory receptor 78 (Olfr78) is shown here to be involved in sensing hypoxia. The receptor is expressed in the carotid body, as well as in the nose. The receptor is activated by the lactate that accumulates when oxygen declines and Olfr78 null mouse mutants fail to increase breathing in hypoxia. This finding raises the possibility that synthetic agonists and antagonists of Olfr78 might be of use in the therapeutic control of breathing and other responses that it controls.