Phosphodiesterase 3 inhibitor attenuates cough response in a sensitized guinea pig model / 中国病理生理杂志

ABSTRACT

AIM: To investigate the effects of selective phosphodiesterase 3 inhibitor olprinone on cough response in guinea pigs sensitized and challenged with ovalbumin. METHODS: Forty sensitized guinea pigs were randomly divided into control ( n = 10), challenged ( n = 10), olprinone ( n = 10) and aminophylline group ( n = 10 ). Two hours after challenged with the aerosol of 1% ovalbumin or saline, animals were intraperitoneally injected either with saline,25 mg/kg of olprinone or 25 mg/kg aminophylline. At 24 h, the injection was repeated with 2. 5 mg/kg and 25 mg/kg olprinone or 2. 5 mg/kg and 25 mg/kg aminophylline respectively in olprinone and aminophylline group, cough response to inhaled capsaicin and airway responsiveness to methacholine (PC150) were measured. Then, total cell number and differential counts were analyzed in bronchoalveolar lavage fluid. RESULTS: The cough frequency was (5 ± 2) times/3 min in control group and (24 ± 3 ) times/3 min in challenged group ( P ＜ 0. 05 ), while PC150 was (659 + 57 ) mg/L in control group and (238 + 67 ) mg/L inchallenged group ( P ＜ 0. 05 ). 25 mg/kg olprinone significantly inhibited the augmented cough response and airway hyperresponsiveness, the cough frequency and PC150 were (15 ±2) times/3 min and (580 ±45) mg/L (P ＜ 0. 05 ), which differed significantly from (18 ± 2) times/3 min and (438± 52) mg/L in aminophilline group (P ＜ 0. 05). However, olprinone failed to reverse the elevated total cell number and percentage of eosinophils in bronchoalveolar lavage fluid from guinea pigs challenged with ovalbumin (P ＞ 0. 05 ). CONCLUSION: Phosphodiesterase 3 inhibitor attenuates cough response associated with eosinophilic airway inflammation by bronchodilatory effect.