Cough reflex sensitivity can be enhanced by coincident activation of airway afferent nerve subtypes. Coughing was evoked electrically from the tracheal mucosa of anesthetized guinea pigs. Optimal stimulation frequencies (16 Hz) and pulse duration were maintained during 10 second stimuli delivered at varying stimulation voltages. The percentage of animals coughing at various voltages was determined in animals inhaling saline (black bars) or the C-fiber stimulant bradykinin (1mg/ mL; grey bars).
This graph is reproduced with permission from Mazzone et al. (43).
Mazzone SB, Mori N, Canning BJ. Synergistic interactions between airway afferent nerve subtypes regulating the cough reflex in guinea-pigs. J Physiol 2005;569:559-73.