Effects of combined bronchodilators and oscillations on the the airway smooth muscle response

Mathur, Meha
Al-Jumaily, Ahmed
Cairns, Simeon
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Master of Philosophy
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Auckland University of Technology

The current study aims to investigate the combined effects of oscillations and bronchodilators on the dynamics of the isolated contracted airway smooth muscle. Current day asthma treatments commonly use bronchodilators such as Isoproterenol to reduce the symptoms of asthma. Previous studies have shown the ability of length oscillations (such as those occurring during tidal breathing and deep inspirations) to have a bronchodilatory effect on normal activated airway smooth muscle both in vitro and in vivo. However, this effect is absent or transient in asthmatic airway smooth muscle. Although, many studies have been conducted to possibly understand the role of oscillations on the airway smooth muscle (ASM) dynamics, the exact mechanism is still unclear. Many studies have been conducted to look at the effects of length oscillations or perturbations on the contracted ASM dynamics, along with separate set of studies investigating the behaviour of ASM in the presence of bronchodilators. This study is novel in the sense that it experimentally investigates the effects of bronchodilators combined with length oscillations of varying parameters on the isolated airway smooth muscle. The experimental data suggest that the combined effect of the bronchodilator Isoproterenol and length oscillations is higher than that of each when applied alone. This response has been tested by varying the amplitudes and frequencies of the oscillations. The relaxation of the ASM subsequent to the application of oscillations was found to be proportional to the amplitude, but independent of the frequency of oscillations. This study gives more insight into the role of bronchodilators and oscillations (such as while breathing) on the contracted airways in an optimal goal of developing a new treatment methodology for asthma.

Airway smooth muscle , Asthma , Length oscillations
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