Abstract: Objective To investigate the reactivity of intrapulmonary arterial rings to vasoactive substances as thromboxane A2
and endothelin-1 in patients with chronic obstructive pulmonary disease (COPD). Methods Intrapulmonary arterial rings
isolated from patients with normal lung function and COPD were mounted in a Multi Myograph system to determine the
reactivity of the intrapulmonary arterial rings to 60 mmol/L KCl, thromboxane A2 analogue U46619 and endothelin-1 before
and after preconditioning with the COX synthase inhibitor indomethacin. Results The reactivity of intrapulmonary arterial
rings to U46619 and endothelin-1 was significantly decreased in patients with COPD. The reactivity to U46619 was
dramatically decreased in patients with normal lung function after application of indomethacin. Conclusion The reactivity of
intrapulmonary arterial rings is significantly decreased in patients with COPD.