Non-specific Airway Hyperreactivity in Isolated Respiratory Preparations from Guinea-pigs Sensitized and Challenged with Ovalbumin

✍ Scribed by C.A. Lewis; D. Raeburn; K.J. Broadley

• Publisher: Elsevier
• Year: 1994
• Tongue: English
• Weight: 417 KB
• Volume: 7
• Category: Article
• ISSN: 0952-0600
• DOI: 10.1006/pulp.1994.1037

✦ Synopsis

SUMMARY: Airway hyperreactivity to physical, chemical, immunological and pharmacological stimuli is well documented in vivo. The aim of this study was to investigate whether tissues taken from guinea-pigs that had been shown to display hyperreactivity in vivo after antigen challenge were also hyperreactive in vitro. Isolated airwayperfused lungs from ovalbumin-sensitized guinea-pigs challenged (24 \mathrm{~h}) beforehand with an aerosol of ovalbumin showed a significant ((P<0.05)) increase in responsiveness to the bronchoconstrictor response to a bolus dose of carbachol ( (10 \mu \mathrm{g}) ) when compared with saline challenged animaks. The contractile responses to single doses of carbachol ((10 \mu \mathrm{g})) and histamine ( (30 \mu \mathrm{g})) in immersed tracheal spiral preparations taken from sensitized animals exposed to the ovalbumin were also significantly enhanced ( (P<0.05) ). A non-significant leftward shift was observed in the concentration-response curve for histamine in challenged perfused lungs from ovalbumin-challenged animals compared with an (\mathrm{NaCl}) challenge. Concentration-response curves to carbachol and histamine in immersed tracheal spirals were virtually superimposed. Therefore, this study has shown non-specific airway hyperreactivity of isolated airway perfused lungs at (24 \mathrm{~h}) following a challenge of sensitized guinea-pigs with aerosolized ovalbumin, although this was not evident from concentration-response curves in immersed trachea. The isolated perfused lung therefore provides a simple method for further evaluation of the mechanisms of airway hyperreactivity.