Am. J. Respir. Crit. Care Med., Vol 149, No. 2, Feb 1994, 382-386.
Human bronchial smooth muscle responsiveness after in vitro exposure to acrolein
A Ben-Jebria, R Marthan, M Rossetti, JP Savineau and JS Ultman
Laboratoire de Physiologie, Faculte de Medecine Victor Pachon, Universite de Bordeaux II, France.
Human isolated bronchi obtained at thoracotomy from 42 patients were
exposed to aqueous solutions of acrolein, and the resulting change in
contractile responses was evaluated by measuring agonist cumulative
concentration-response curves (CCRC). Contractile responses to carbachol
were measured after a variety of exposure concentrations, from 0.01 to 3.0
microM, and at times from 5 to 60 min. The optimal condition to induce
airway smooth muscle hyperresponsiveness was an exposure duration of 20 min
at a concentration of 0.3 microM. The effect of acrolein exposure on human
bronchial smooth muscle was also assessed by examining the contractile
responses to potassium chloride (KCl), histamine, and neurokinin A (NKA) in
both the absence and the presence of phosphoramidon. Although in vitro
exposure of the human bronchus to 0.3 microM acrolein did not alter
responses to KCl, it did increase the efficacy of carbachol and NKA without
altering their potency. This concentration of acrolein also increased the
contractile response to low concentrations of histamine and shifted the
CCRC to the left. Pretreatment with phosphoramidon abolished the
differential effect of acrolein on airway response to NKA. These results
suggest that the mechanism of action of acrolein includes inactivation of
airway neutral endopeptidase as well as alterations in the
pharmacomechanical, but not the electromechanical, coupling of human
bronchial smooth muscle.