The effect of chemical stimulation of esophageal mucosa on citric acid induced cough and specific airway resistance in guinea pig.

BACKGROUND

Gastroesophageal reflux disease is one of the most common causes of chronic cough. The mechanism of the cough initiation in these patients remains unresolved.

OBJECTIVES

This study was designed to investigate the effect of intraesophageal (IE) administration of capsaicin on cough and specific airway resistance (Saw) in guinea pigs.

METHODS

Male TRIK strain guinea pigs were used. In the first experiment 12 controls received IE saline, 9 animals (group 1) received IE capsaicin (400 microM, 0.2 ml) and 12 guinea pigs (group 2) received IE capsaicin (400 microM, 0.2 ml) 24 hours after IE administration of hydrochloric acid (3 M, 0.2 ml). Cough induced by inhalation of citric acid (CA) and Saw was determined after IE administration of saline in controls and capsaicin in groups 1 a 2. In the second experiment, CA induced cough was determined in guinea pigs (n=13) in the beginning of the study (control response), after NaOH (1 M, 0.2 ml) was administered IE. One week later in conditions of corrosive esophagitis CA induced cough was determined after IE administration of capsaicin (cough during esophageal stimulation).

RESULTS

There was no difference in CA induced cough between controls, group 1 and 2 (p=0.98). Saw was hot affected by IE capsaicin stimulation and CA inhalation in group 1 and group 2. There was no difference found between control cough response and those induced after IE capsaicin in animals with corrosive esophagitis (p=0.75).

CONCLUSION

Esophageal stimulation with capsaicin did not trigger and/or modulate CA induced cough and Saw in guinea pigs models. (Fig. 5, Ref. 22.)