The effects of leukotrienes, thromboxane A2 and phospholipase A2 on human, porcine and guinea pig lung parenchyma

Abstract

A comparison was made of the contractions, induced by LTD₄, histamine and phospholipase A₂ in parenchymal strips of guinea pig (GPLP), porcine and human lung in a cascade superfusion system. The effects of LTD₄ and phospholipase A₂ on the release of TxA₂ in these tissues and of TxA₂, 5-HT and acetylcholine on the GPLP were also determined. In the GPLP strip, the LTC₄-induced contractions are due for±80% to the release of TxA₂ and for±20% to the direct effect of LTC₄. The guinea pig tissue displayed the highest sentivity towards all substances, except to the contraction induced by histamine, which was most effective in the porcine tissue. Low activities wer found in the human tissue in all tests. The reason for these effects may be a difference in activities or number of cell types which participate in the reactions leading to the contractions.