Insulin Induced Airway Hyper-Responsiveness Pak Armed Forces Med J 2016; 66(5):726-30 726 PROTECTIVE EFFECT OF SALBUTAMOL AND MONTELUKAST AGAINST INSULIN INDUCED AIRWAY HYPER-RESPONSIVENESS IN GUINEA PIG AIRWAYS IN VITRO

Objective: To evaluate and compare the protective effects of salbutamol and montelukast in amelioration of insulin induced airway hyper-reactivity on isolated tracheal smooth muscle of guinea pig in vitro. Study Design: Laboratory based randomized control trials (Experimental study). Place and Duration of Study: Pharmacology Department and Centre for Research in Experimental and Applied Medicine (CREAM) Army Medical College Rawalpindi from January 2012 to September 2012. Material and Methods: Effects of variable doses of insulin (10-7-10-3 M) and insulin pretreated with salbutamol (10-6 M) and montelukast (10-5 M) were observed on airways of guinea pig in vitro by constructing cumulative dose response curves. Four Channel Oscillograph and Transducer were used to record the tracheal smooth muscle contractions. Results: Insulin induced a dose dependent reversible contraction of isolated tracheal muscle of guinea pig. The maximum response of insulin and insulin pretreated with salbutamol and montelukast were 35 ± 1.13 mm, 14.55 ± 0.62 mm and 34.5 ± 1.024 mm respectively. So salbutamol significantly inhibited the contractile response of insulin while montelukast failed to counteract the airway hyper-reactivity induced by insulin. Conclusion: Salbutamol significantly inhibited the contractile response of insulin, while montelukast did not produce statistically significant effect on insulin induced airway hyper-reactivity. So it is suggested that pretreatment of inhaled insulin with salbutamol may be beneficial in inhibiting the broncho-constriction induced by insulin.