Effect of tachykinin on cough response in an ovalbumin-sensitized guinea pig model

AIM: To investigate the role of tachykinin in airway in cough response in guinea pigs sensitized and challenged with ovalbumin. METHODS: 20 normal and 20 sensitized guinea pigs were challenged with the aerosol of ovalbumin. twenty-four hours later, cough response to inhaled capsaicin was measured after the normal and sensitized guinea pigs (10 of each) introperitoneally injected either with 0.1 mg/kg, 0.3 mg/kg and 1.0 mg/kg of NK1 antagonist SR140333 or NK2 antagonist SR48968, respectively. Specific airway resistance was recorded with noninvasive technique. RESULTS: Cough response increased in sensitized guinea pigs compared with control ［(19.5±5.7） times/3 min vs （9.3±1.2） times/3 min, P<0.05］. SR48968FR decreased the cough response by 30% in control guinea pigs (P<0.05), but SR140333 did not. Both prevented an increase in airway resistance after the inhalation of capsaicin. However, SR48968FR and SR140333 inhibited increased cough response ［(9.9±4.7） times/3 min, （8.0±1.6） times/3 min, P<0.05］ and airway resistance induced by the inhalation of capsaicin. CONCLUSION: Neurokinin (NK) antagonist inhibits increased cough response in guinea pigs sensitized and challenged with ovalbumin. Tachykinin may be an important mediator in cough associated with eosinophilic airway inflammation.