Enkephalinase inhibitor potentiates mammalian tachykinin-induced contraction in ferret trachea.

摘要: To determine the roles of endogenous enkephalinase (EC.3.4.24.11) in regulating tachykinin-induced contraction airway smooth muscle, authors studied effects inhibitor leucine-thiorphan on contractile responses to substance P (SP), neurokinin A (NKA) and B (NKB) isolated ferret tracheal muscle segments. Leucine-thiorphan shifted, concentration-dependent fashions, dose-response curves all tachykinins lower concentrations. changed rank order tachykinin potency from NKA greater than SP NKB = SP. Removal epithelium slightly enhanced but not NKB. Atropine shifted higher Each increased response electrical field stimulation (5 Hz, 20 sec duration, V) a dose-dependent fashion. This effect was altered by hexamethonium, indomethacin, BW755C or naloxone potentiated inhibited receptor antagonist (D-Pro2, D-Trp7,9)-SP atropine. Because did affect acetylcholine significantly, their were probably presynaptic postganglionic nerves. Captopril, bestatin leupeptin alter responses, suggesting that angiotensin converting enzyme, aminopeptidases serine proteinases modulate effects. Enkephalinase immunofluorescence found confirmed authors' finding enkephalinase-like activity muscle. The results suggest is an important modulator