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Enkephalinase inhibitors potentiate tackykinin-induced release of /sup 35/SO/sub 4/-labeled macromolecules from ferret trachea

Conference · · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)
OSTI ID:5325405

To study the roles of tachykinins and endogenous proteinases in regulating secretion from ferret tracheal glands, the authors measured the release of /sup 35/SO/sub 4/-labeled macromolecules after incubating segments of trachea in Ussing chambers in the presence of /sup 35/SO/sub 4/. 85% of the total macromolecular radioactivity was in fractions of molecular weights greater than or equal to 10/sup 6/. The response to substance P (SP) was concentration-dependent, with a threshold of 10/sup -9/ M, and responses to 10/sup -6/M and 10/sup -5/M of 87 +/- 9 and 156 +/- 26 pmol/cm/sup 2//h, respectively (n = 6 ea). The enkephalinase inhibitor, thiorphan, increased the secretory response to SP (10/sup -6/M) in a concentration-dependent fashion, with a threshold of 10/sup -8/M, and a response to SP after 10/sup -4/M thiorphan of 268 +/- 58 pmol/cm/sup 2//h (p < 0.05; n = 6). Phosphoramidon also increased SP-induced secretion to 334 +/- 69 pmol/cm/sup 2//h (p < 0.005; n = 4), and also potentiated the secretory responses to neurokinins A and B, physalaemin, eledoisin, and kassinin, but did not potentiate the secretory responses to either bradykinin or vasoactive intestinal peptide. Other proteinase inhibitors did not potentiate SP-induced secretion. These results suggest that enkephalinase in the airway degrades tachykinins, and may therefore play a role in regulating tachykinin-induced effects.

Research Organization:
Univ. of California, San Francisco
OSTI ID:
5325405
Report Number(s):
CONF-8604222-
Journal Information:
Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Vol. 45:3; ISSN FEPRA
Country of Publication:
United States
Language:
English