The carotid body is essential for the adaptation of mammals to environmental or pathological conditions that result in hypoxemia. The carotid body contains neuron-like O2-sensitive glomus cells. In response to hypoxia, these cells release neurotransmitters that rapidly activate afferent sensory fibers stimulating the respiratory center and inducing hyperventilation. The mechanisms that glomus cells utilize to detect changes in blood O2 tension have remained unclear. Single dissociated glomus cells can respond robustly to hypoxia when superfused with standard, lactate-free hypoxic solutions. As such, it was surprising that Chang et al. Nature 2015 claimed that lactate activation of an odorant receptor (Olfr78), which is expressed in glomus cells, is required for oxygen regulation of breathing. Here we report that we are unable to replicate these findings. We show that Olfr78-null mice (Bozza et al. Neuron 2009) have a normal hypoxic ventilatory response. In addition, we show that the physiological responses of single glomus cells to hypoxia and lactate are indistinguishable between wild-type and Olfr78-null mice.
Europhysiology 2018 (London, UK) (2018) Proc Physiol Soc 41, SA052
Research Symposium: Olfr78 is not required for oxygen regulation of breathing in mice
H. Torres-Torrelo2,5, P. Ortega-Sáenz2,5, D. Macías3, M. Omura1, T. Zhou4, H. Matsunami4, R. Johnson3,6, P. Mombaerts1, J. López-Barneo2,5
1. Max Planck Research Unit for Neurogenetics, Frankfurt, Germany. 2. Instituto de Biomedicina de Sevilla, Sevilla, Spain. 3. Department of Physiology, Development & Neuroscience, University of Cambridge, Cambridge, Spain. 4. Department of Neurobiology and Duke Institute for Brain Sciences, Duke University Medical Center, Durham, North Carolina, United States. 5. Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas, Sevilla, Spain. 6. Department of Cell and Molecular Biology, Karolinska Institute, Stockholm, Sweden.
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Where applicable, experiments conform with Society ethical requirements.