Peripheral cough reflex sensory pathway

The peripheral cough reflex sensory pathway is a physiological system comprising sensory nerve fibers that detect mechanical, chemical, and thermal stimuli in the respiratory tract. These fibers, primarily Aδ-fibers and C-fibers traveling within the vagus nerve, transmit afferent signals to the cough center in the medulla oblongata to trigger the cough motor program (StatPearls, Physiology, Cough Reflex). Key molecular transducers within this pathway include P2X3 receptors, TRPV1, and TRPA1 channels, which respond to ATP, heat, and irritants, respectively (Mazzone & Undem, Physiological Reviews, 2016). In conditions such as chronic cough and cough hypersensitivity syndrome, these peripheral nerves exhibit increased sensitivity, leading to a state of neuronal hyper-excitability (Chung, Lung, 2014). Therapeutic strategies targeting this pathway aim to modulate these sensory inputs using P2X3 antagonists or peripheral antitussives like benzonatate to reduce the urge to cough (Morice et al., European Respiratory Journal, 2020). However, complete suppression of this pathway is avoided to maintain the essential protective function of coughing for clearing mucus and foreign particles from the lungs (Canning, Frontiers in Physiology, 2014). This pathway is a major focus for drug development in respiratory medicine, particularly for patients with refractory or unexplained chronic cough. Understanding the heterogeneity of the sensory nerves involved is crucial for developing more selective and effective antitussive therapies.

Other names

Cough reflex arcAirway sensory pathwayVagal afferent pathwayPeripheral tussive pathway

Antagonism of sensory receptors (e.g., P2X3) or inhibition of voltage-gated sodium channels on peripheral airway afferents to reduce tussive signal transmission.