Inhibition of neutral endopeptidase potentiates compound 48/80-induced constriction of guinea-pig tracheal smooth muscle.
Pulm Pharmacol
; 7(5): 343-7, 1994 Oct.
Article
em En
| MEDLINE
| ID: mdl-7542950
ABSTRACT
Our previous studies have shown that the inhibition of neutral endopeptidase, an enzyme which degrades tachykinins, increases anaphylactic construction of guinea-pig tracheal smooth muscle. To investigate this observation further, we examined the effects of phosphoramidon, an inhibitor of a neutral endopeptidase, on constriction induced by the non-immunological mast cell degranulator-compound 48/80. Phosphoramidon produced significant leftward shift of the compound 48/80 concentration-response curve with corresponding decrease in the EC50 value from 51 (28-80) micrograms/ml to 42 (20-72) micrograms/ml. When added during the compound 48/80-induced constriction, phosphoramidon significantly increased the magnitude of this constriction by 69.7% after 30 min, and 78.9% after 45 min. Phosphoramidon was ineffective in tracheal rings from tachykinin-depleted guinea pigs. The incubation of tracheal rings with H1-histamine receptor antagonist (diphenhydramine HCl, 10 microM) and leukotriene receptor antagonist (ICI 198.615, 5 microM) significantly diminished the contractile response to compound 48/80 and prevented a phosphoramidon-dependent increase of this constriction. These results suggest that compound 48/80 induces the release of tachykinins by the stimulatory activity of histamine and leukotrienes. Anaphylactic release of tachykinins would therefore not depend directly on the antigen-antibody reaction.
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Base de dados:
MEDLINE
Assunto principal:
Inibidores de Proteases
/
Traqueia
/
Neprilisina
/
P-Metoxi-N-metilfenetilamina
/
Músculo Liso
Idioma:
En
Ano de publicação:
1994
Tipo de documento:
Article