Receptors responding to changes in upper airway pressure

Area of Science:

• Neuroscience
• Respiratory Physiology

Background:

• Upper airway pressure changes significantly impact respiratory control.
• The specific receptors mediating these responses remain incompletely characterized.

Purpose of the Study:

• To characterize receptors in the superior laryngeal and glossopharyngeal nerves that respond to alterations in upper airway pressures.
• To elucidate the functional role of these receptors in respiratory control.

Main Methods:

• Experiments were conducted on decerebrate, vagotomized, paralyzed, and ventilated cats.
• Transmural pressures in upper airway segments were manipulated.
• Single-fiber activities in the superior laryngeal and glossopharyngeal nerves were recorded.

Main Results:

• Most superior laryngeal receptors discharged tonically; approximately half decreased activity with pressure reduction, while the other half increased.
• Pressure increases modulated activity in Group A and varied responses in Group B superior laryngeal receptors.
• Silent receptors in both nerves were activated by pressure changes, and most receptors showed incomplete adaptation to sustained pressures.

Conclusions:

• Both tonically active and silent receptors in the superior laryngeal and glossopharyngeal nerves are sensitive to upper airway pressure variations.
• These receptors exhibit incomplete adaptation, suggesting a significant role in respiratory reflexes.
• The identified receptors are likely crucial for modulating hypoglossal nerve activity in response to airway pressure fluctuations.