Decreased airway narrowing and smooth muscle contraction in hyperresponsive pigs

Debra Turner, Peter Noble, M.P. Lucas, Howard Mitchell

Research output: Contribution to journalArticlepeer-review

17 Citations (Web of Science)


Increased smooth muscle contractility or reduced smooth muscle mechanical loads could account for the excessive airway narrowing and hyperresponsiveness seen in asthma. These mechanisms were investigated by using an allergen-induced porcine model of airway hyperresponsiveness. Airway narrowing to electric field stimulation was measured in isolated bronchial segments, over a range of transmural pressures (0-20 cmH(2)O). Contractile responses to ACh were measured in bronchial segments and in isolated tracheal smooth muscle strips isolated from control and test (ovalbumin sensitized and challenged) pigs. Test airways narrowed less than controls (P <0.0001). Test pigs showed reduced contractility to ACh, both in isolated bronchi (P <0.01) and smooth muscle strips (P <0.01). Thus isolated airways from pigs exhibiting airway hyperresponsiveness in vivo are hyporesponsive in vitro. The decreased narrowing in bronchi from hyperresponsive pigs may be related to decreased smooth muscle contractility. These data suggest that mechanisms external to the airway wall may be important to the hyperresponsive nature of sensitized lungs.
Original languageEnglish
Pages (from-to)1296-1300
JournalJournal of Applied Physiology
Publication statusPublished - 2002


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