Inhibition of antigen-induced contractions of ileum segments and lung parenchymal strips of actively sensitized guinea pigs by different anti-allergic agents in vitro.

Different types of anti-allergic agents have been compared for their ability to inhibit the antigen-induced contraction of isolated lung parenchymal strips and ilea of guinea pigs. Extremely low concentrations of the lipoxygenase inhibitor NDGA inhibit the contraction of the lung parenchymal strips and higher concentrations block the ileal phase II-contraction (both predominantly caused by the developing SRS-A), but do not inhibit ileal phase I-contraction (caused by released histamine). The H1-antihistamine clemastine predominantly antagonizes phase I of the ileum contraction, and the anti-allergic drug oxatomide reduces all three types of contraction. The degranulation inhibitor DSCG does not influence the contraction of the lung strip, but produces a slight inhibition of both ileal contractions. The PAF-antagonist BN 52021 influences these three contractions in the opposite way to DSCG. As these various types of anti-allergic agents influence these three contractions in a different manner, the models can be used for judging the mechanism of action of a new anti-allergic compound.