Spasmogenic activity of C5adesArg anaphylatoxin on guinea pig lung parenchymal strips: sensitivity of the leukotriene-mediated component to cyclooxygenase inhibitors.

The leukotriene-dependent component of C5adesArg-induced contractile activity on guinea pig lung parenchymal strips is inhibited by cyclooxygenase inhibitors. Indomethacin simultaneously increased leukotriene release while inhibiting both cyclooxygenase-dependent mediator release and the contractile force generated. Tissue responses to LTC4 and LTD4 are also inhibited by cyclooxygenase blockade, while contractions induced by the thromboxane A2 analog, U-46619, histamine or acetylcholine are not affected. These data indicate a functional role for cyclooxygenase metabolites in leukotriene-induced contractile responses in lung.