Phosphodiesterase 3 inhibitor attenuates cough response in a sensitized guinea pig model

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(P0.05),while PC150 was(659±57) mg/L in control group and(238±67) mg/L in challenged group(P0.05).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(P0.05),which differed significantly from(18±2) times/3 min and(438±52) mg/L in aminophilline group(P0.05).However,olprinone failed to reverse the elevated total cell number and percentage of eosinophils in bronchoalveolar lavage fluid from guinea pigs challenged with ovalbumin(P0.05).CONCLUSION:Phosphodiesterase 3 inhibitor attenuates cough response associated with eosinophilic airway inflammation by bronchodilatory effect.