LEUKOTRIENE-D4 POTENTIATES HISTAMINE-INDUCED BRONCHOCONSTRICTION IN GUINEA-PIGS

Abstract

Histamine concentration-response curves performed on isolated airways smooth muscle preparations were unaffected by threshold constrictor concentrations of LTD4 (194 +/- 34 pM for parenchymal strips and 1940 +/- 480 pM for isolated trachea, respectively). In contrast, LTD4, when administered between 2 and 60 s beforehand, potentiated bronchoconstrictor responses to histamine in anaesthetized, artificially ventilated guinea-pigs. Doses of LTD4, which did not produce direct effects on airways resistance, potentiated histamine-induced bronchoconstriction to a lesser degree than those having small direct effects. This potentiation was prevented by bilateral vagotomy. In addition, the antagonists..