Inhibitory effect of N-(3,4-dimethoxycinnamoyl)anthranilic acid on release of SRS from alveolar macrophages in vitro.

The effects of N-(3,4-dimethoxycinnamoyl)anthranilic acid (N-5') on the release of the slow-reacting substance (SRS) by zymosan- or Ca ionophore-stimulated rat and human alveolar macrophages (AM) were examined in vitro. Disodium cromoglycate (DSCG) was used as a control. N-5' at concentrations of 10(-4)-10(-3) M significantly inhibited the release of SRS from both rat and human AM stimulated by zymosan. N-5' had almost the same inhibitory effect when added to the AM culture system at any time from 180 min before to 30 min after the addition of zymosan. N-5' (10(-4)-10(-3) M) also significantly inhibited the release of SRS by Ca ionophore-stimulated rat AM. N-5' (10(-6)-10(-3) M) had no significant effect on phagocytosis of yeast particles by rat AM. DSCG (10(-6)-10(-3) M) did not inhibit the release of SRS from the zymosan-stimulated rat AM. N-5' was concluded to have a relatively specific inhibitory effect on the non-immunological release of SRS from stimulated AM. It is postulated that N-5' inhibits the process of release of SRS from AM by acting after the initial stage.