Characterisation of receptors mediating the contractile effects of prostanoids in guinea-pig and human airways

Receptors mediating the contractile effects of prostanoids in the airways of guinea-pig and man have been compared using a range of selective agonists and antagonists. In guinea-pig and human lung parenchymal strips, contractile responses to all prostanoid agonists were blocked by EP092 and AH23848 (antagonists of thromboxane-sensitive receptors) but were unaffected by the EP1 receptor antagonist, AH6809. In guinea-pig tracheal rings responses to the thromboxane mimetic U46619 were antagonised by EP092 and AH23848. AH6809 was ineffective, but did antagonise responses to 16,16-dimethylPGE2 and PGF2 alpha in this tissue. In the human bronchiolar ring responses to U46619 were poorly antagonised by AH23848, EP092 and AH6809. The results suggest that prostanoid contractile agonists act through thromboxane receptors in guinea-pig and human lung parenchymal strips and through thromboxane and EP1 receptors in guinea-pig trachea. A novel prostanoid receptor type, or subtype, mediating contractile effects may be present in human bronchioles.