Pulmonary C-fiber activation before and after peptidase inhibition in rats

D. R. Bergren, E. E. Ustinova, H. D. Schultz

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


Inhibition of peptidases within the lungs not only potentiates the effects of neuropeptides released from C-fibers but also the effects of bradykinin and capsaicin both of which stimulate C-fibers. To determine if peptidase inhibition potentiates C-fiber activation, we challenged pulmonary C-fibers in rats with capsaicin or bradykinin before and after inhibition of neutral endopeptidase (NEP) or angiotensin converting enzyme (ACE). Inhibition of NEP by phosphoramidon (10 mg/kg, i.v.) potentiated the effect of capsaicin (0.5-1 μg, i.v.) on C-fiber activity but did not change the response to bradykinin (1-2 μg, i.v.). Inhibition of ACE by captopril (5 mg/kg, i.v.) potentiated C-fiber activation by either bradykinin or capsaicin. Aerosol administration of either phosphoramidon (1 x 10-5 M, 2 min) or captopril (4.6 x 10-3 M, 2 min) potentiated C-fiber activation by capsaicin aerosol (1.6 x 10-4 M, 1 min) but not by bradykinin aerosol (9.4 x 10-5 M, 1 min). Therefore, inhibition of NEP or ACE may potentiate airway obstructive mechanisms initiated by C-fiber stimulation.

Original languageEnglish (US)
Pages (from-to)99-109
Number of pages11
JournalRespiration Physiology
Issue number2
StatePublished - Feb 1997


  • C-fibers
  • bradykinin
  • capsaicin
  • captopril
  • lung
  • phosphoramidon
  • pulmonary afferents

ASJC Scopus subject areas

  • Physiology
  • Pulmonary and Respiratory Medicine


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