Disodium Cromoglycate (DSCG) is now an established drug in the prophylaxis of asthma. It selectively suppresses the specific immunological pathways leading to the release of chemical mediators.
The present investigation was conducted to demonstrate the effect of DSCG on the action of various broncho-active agents in guinea pig tracheal strips.
Male guinea pigs, weighing 250-300g, were sacrificed. Guinea pig trachea was removed, cut spirally in strips 1.0-1.5mm in width and 3.0-4.0cm in length, suspended in bioassay glass jackets, superfused with Krebs-Henseleit solution at 37°C and saturated with oxygen and carbon dioxide (95:5, v/v). Contraction and relaxation of tracheal strips were detected by an isotonic transducer and displayed on a polyrecorder.
1) DSCG attenuated the acetylcholine-induced contractile responses in guinea pig tracheal strips, and shifted the dose-response curve of acetylcholine downward. The shift became dominant by increasing the dose.
2) DSCG attenuated the histamine, serotonin-, bradykinin- and PGF2α -induced contractile responses in guinea pig tracheal strips dose-dependently.
3) DSCG potentiated the isoproterenol-, epinephrine-, PGE2- and salbutamol-induced relaxation responses in guinea pig tracheal strips, and shifted the dose-response curves downward. The shift became dominant by increasing the dose.
The above results may suggest that DSCG has not only an inhibiting action on the release of various chemical mediators from mast cells, but also has an attenuating effect on the action of bronchoconstrictors and an potentiating effect on the action of bronchodilators.
