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Oxygen sensing in airway chemoreceptors
1Department of Pathology, Hospital for Sick Children, Toronto, Ontario, Canada.
Nature
|September 9, 1993
Summary
Pulmonary neuroepithelial bodies, which sense oxygen levels, were found to have an oxygen-sensitive potassium channel. This discovery suggests these airway cells act as chemoreceptors regulating breathing during hypoxia.
Area of Science:
- Pulmonary physiology
- Cellular biology
- Respiratory neuroscience
Background:
- Pulmonary neuroepithelial bodies (NEBs) are innervated cell clusters in the airway mucosa.
- NEBs are structurally similar to chemoreceptors and hypothesized to sense hypoxia.
- The precise mechanism of oxygen sensing in NEBs remains unknown.
Purpose of the Study:
- To investigate the cellular mechanisms underlying oxygen sensing in pulmonary neuroepithelial bodies.
- To identify ion channel activity and molecular components involved in hypoxia detection in NEBs.
Main Methods:
- Culture of rabbit fetal lung neuroepithelial bodies.
- Whole-cell patch clamp electrophysiology to record ion currents.
- Identification of plasma membrane proteins using biochemical assays.
Main Results:
- Voltage-activated potassium, calcium, and sodium currents were identified in NEB cells.
- Hypoxia caused a reversible 25-30% reduction in outward potassium current.
- An oxygen-binding protein (b-cytochrome, NADPH oxidase) was found on the NEB cell plasma membrane.
Conclusions:
- Pulmonary neuroepithelial bodies possess an oxygen-sensing mechanism involving O2-sensitive potassium channels and sensor proteins.
- These findings identify NEBs as transducers of the hypoxia stimulus.
- This supports the role of NEBs as airway chemoreceptors in respiratory regulation.