Effect of neutral endopeptidase inhibition of f-Met-Leu-Phe-induced bronchoconstriction in the rabbit

M. J. Peters*, K. Panaretto, L. Kemsley, A. B X Breslin, N. Berend

*Corresponding author for this work

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

Inhalation of f-Met-Leu-Phe (FMLP) produces dose-dependent increases in pulmonary resistance (RL) in rabbits. We hypothesized that inhibition of neutral endopeptidase (NEP), which has high affinity for FMLP, would augment the response to FMLP inhalation. We found the increase in RL above baseline in response to FMLP to be reduced from 56 ± 18 to 8 ± 10% (P < 0.01) by phosporamidon (1 mg/kg) and to 15 ± 6% (P < 0.02) by thiorphan (3 mg/kg). The geometric mean dose of FMLP producing a 20% rise in RL (PC20RL FMLP) was increased by phosphoramidon from 1.1 to 4.5 mg/ml (P < 0.05). Enkephalins, which are also NEP substrates, modulate cholinergic neurotransmission in the airway. Inhibition of the FMLP response by phosphoramidon was reversed by coadministration of naloxone (0.1 mg/kg); after atropine (2 mg/kg) the change in RL in response to FMLP was reduced to 7 ± 4% (P < 0.01), whereas morphine (0.15 mg/kg) increased PC20RL FMLP to 5.1 mg/ml (P < 0.05). FMLP-induced bronchoconstriction in the rabbit is vagally mediated, and reduced responses after NEP inhibition may reflect modulation of cholinergic bronchoconstriction by enkephalins. Changes in airway NEP activity may influence the activity of a wide range of its substrates, of which some are bronchoconstrictors and others bronchodilators.

Original languageEnglish
Pages (from-to)877-881
Number of pages5
JournalJournal of Applied Physiology
Volume70
Issue number2
Publication statusPublished - 1991
Externally publishedYes

Keywords

  • bacterial peptides
  • cholinergic bronchoconstriction
  • enkephalin
  • membrane metalloendoproteinase
  • substance P

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