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DUAL MODES OF ACTION FOR DISODIUM CROMOGLYCATE IN INHIBITION OF ANTIGEN‐INDUCED CONTRACTIONS OF GUINEA‐PIG ISOLATED AIRWAYS SMOOTH MUSCLE
Author(s) -
Stewart A. G.,
Fennessy M. R.
Publication year - 1983
Publication title -
clinical and experimental pharmacology and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 103
eISSN - 1440-1681
pISSN - 0305-1870
DOI - 10.1111/j.1440-1681.1983.tb00228.x
Subject(s) - ovalbumin , isoprenaline , fenoterol , histamine , guinea pig , chemistry , endocrinology , medicine , pharmacology , antigen , stimulation , immunology , asthma
SUMMARY 1. Disodium cromoglycate (DSCG; 10 μmol/l‐1 mmol/l) relaxed the tone induced in the guinea‐pig isolated trachea by histamine (5 μmol/l). Both isoprenaline and fenoterol were approximately 1000 times more potent than DSCG in relaxing tracheal smooth muscle. 2. Ovalbumin (1 μg/ml) contracted isolated tracheal and parenchymal strips from sensitized guinea‐pigs. The sensitization procedure used was selective for eliciting IgG antibody production. 3. In concentrations equieffective for relaxation of the isolated trachea, fenoterol (20 nmol/l), isoprenaline (60 nmol/l) and DSCG (100 μmol/l) inhibited ovalbumin‐induced contractions of both tracheal and parenchymal strip preparations. 4. DSCG produced a significantly greater ( P < 0.05) inhibition of ovalbumin‐induced contractions of isolated trachea than did isoprenaline, suggesting that at 100 μmol/l DSCG produced a greater inhibition of mediator release than that produced by isoprenaline. 5. Compound 48/80 (200 μg/ml) contracted the isolated trachea whereas this concentration had no contractile effect on the parenchymal strip. The failure of DSCG to inhibit compound 48/80 induced contractions of the isolated trachea together with the lack of contractile effect of compound 48/80 on the parenchymal strip suggest that compound 48/80 is inferior to antigenic stimulation as a reliable analogue of immunological activation of mast cells and consequent mediator release. 6. On the basis of DSCG‐induced relaxation of the isolated trachea and greater inhibition of ovalbumin‐induced contractions relative to that produced by isoprenaline, it is concluded that DSCG has dual modes of action in inhibition of antigen‐induced contraction of isolated airways smooth muscle, that is, DSCG produced functional antagonism of antigen‐induced mediators in addition to inhibiting mediator release.