Abstract
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 language | English (US) |
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Pages (from-to) | 99-109 |
Number of pages | 11 |
Journal | Respiration Physiology |
Volume | 107 |
Issue number | 2 |
DOIs | |
State | Published - Feb 1997 |
Keywords
- C-fibers
- bradykinin
- capsaicin
- captopril
- lung
- phosphoramidon
- pulmonary afferents
ASJC Scopus subject areas
- Physiology
- Pulmonary and Respiratory Medicine