Tuyển tập các báo cáo nghiên cứu về y học được đăng trên tạp chí y học 'Respiratory Research cung cấp cho các bạn kiến thức về ngành y đề tài: Airway obstruction in asthma: does the response to a deep inspiration matter. | Available online http content 2 5 273 Commentary Airway obstruction in asthma does the response to a deep inspiration matter Jeffrey J Fredberg Department of Environmental Health Harvard School of Public Health Boston Massachusetts USA o 3 I Correspondence Jeffrey J Fredberg Physiology Program Harvard School of Public Health 665 Huntington Avenue Boston MA 02115 USA. Tel 1 617 432 0198 fax 1 617 432 3468 e-mail jfredber@ Received 1 June 2001 Revisions requested 28 June 2001 Revisions received 30 June 2001 Accepted 16 July 2001 Published 6 August 2001 Respir Res 2001 2 273-275 2001 BioMed Central Ltd Print ISSN 1465-9921 Online ISSN 1465-993X Abstract Airway hyperresponsiveness in asthma may not be a problem of too much airway smooth muscle strength. Rather it may be a problem of too little of the factors that oppose muscle shortening. The weight of available evidence seems to support the idea that loss of the dilating response to a deep inspiration may play a central role in this process and that the locus of the response is within the airway smooth muscle cell. Bridge dynamics and plastic reorganization of the smooth muscle cytoskeleton are the focus of this commentary how these factors interact and details about underlying mechanisms remain unclear. Keywords bronchospasm hyperresponsiveness myosin plasticity Introduction Smooth muscle surrounding the airway shortens when it is activated and as the muscle shortens the airway narrows. In normal individuals subjected to challenge with non-specific contractile agonists the extent of airway narrowing is limited and this limited response is reflected by a plateau of the dose-response curve corresponding to only modest levels of airway narrowing. Asthmatic individuals by contrast are hyperresponsive. Compared with the response in the normal subject the plateau of the dose-response curve in the asthmatic is markedly elevated or abolished altogether indicating that airway smooth .
