Cough reflex pathways

The cough reflex pathways in the pharyngeal mucosa form part of the broader cough reflex arc, a protective neural mechanism that clears the airways of irritants, foreign particles, mucus, and pathogens through coordinated sensory detection and motor response. This reflex is initiated by stimulation of specialized cough receptors—primarily myelinated Aδ fibers (cough receptors) and unmyelinated C-fibers—located in the pharynx, larynx, trachea, and bronchi, which detect mechanical punctate stimuli, acid, capsaicin, bradykinin, and other tussigens. Afferent signals travel via vagus nerve branches (e.g., superior laryngeal nerve) to the cough center in the medulla and pons (nucleus tractus solitarius and related areas), where central integration occurs, potentially involving interactions with higher cortical inputs. Efferent outputs then activate inspiratory muscles (diaphragm via phrenic nerve), glottis closure, and expiratory muscles (abdominals, intercostals) to produce deep inspiration, compression, and explosive expiration exceeding 100 mph to expel material. In disease, hypersensitivity arises from C-fiber sensitization by inflammation, ATP via P2X3 receptors, or crosstalk from esophageal afferents in GERD, leading to chronic refractory cough without identifiable molecular drug targets in the pathways themselves. While not a conventional therapeutic target like a receptor or enzyme, modulation focuses on upstream sensitizers (e.g., potential P2X3 antagonists in development for hypersensitivity), but the pathways represent a physiological process rather than a discrete molecule.

Other names

Cough reflex arccough reflex