Repeated allergen exposure enhances excitatory nonadrenergic noncholinergic nerve-mediated bronchoconstriction in sensitized guinea-pigs

N. Kageyama, M. Ichinose, A. Igarashi, M. Miura, H. Yamauchi, Y. Sasaki, J. Ishikawa, M. Tomaki, K. Shirato

Research output: Contribution to journalArticlepeer-review

13 Citations (Scopus)

Abstract

The effect of repeated allergen inhalation challenge on the airway excitatory nonadrenergic noncholinergic (e-NANC) nerve-mediated bronchoconstrictor response was studied in ovalbumin (OA) sensitized guinea-pigs. Three weeks after sensitization, OA inhalation, 0.03% for 3 min (challenged group), or saline inhalation (control group) was repeated every day for 4 weeks. The e-NANC nerve function was examined in vitro by means of isometric tension measurement of main bronchi. After pretreatment with atropine (10-6 M) and propranolol (10-6 M), we performed electrical field stimulation (EFS) or exogenous neurokinin A (NKA) administration. In the challenged group, EFS-induced main bronchial contraction was significantly greater than that of the control group (p < 0.05 or p < 0.01), but exogenous NKA-mediated responses were almost the same in both groups. The e-NANC-induced main bronchial contractions after EFS were enhanced by pretreatment with the neutral endopeptidase inhibitor, phosphoramidon, to the same degree in the control and challenged groups, indicating that the peptide degradation mechanisms were not impaired even in the challenged group. Substance P immunoreactivities in the lung of the challenged group were significantly higher than those of the control group. These results suggest that chronic airway inflammation after repeated allergen challenge increases excitatory nonadrenergic noncholinergic nerve function, possibly by enhancing sensory neuropeptide production and/or release.

Original languageEnglish
Pages (from-to)1439-1444
Number of pages6
JournalEuropean Respiratory Journal
Volume9
Issue number7
DOIs
Publication statusPublished - 1996

Keywords

  • airway inflammation
  • antigen
  • asthma
  • neutral endopeptidase
  • substance P

ASJC Scopus subject areas

  • Pulmonary and Respiratory Medicine

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