The dual action of meclofenamate on the contractile response to PGF2 alpha in the guinea-pig trachea.
Indomethacin and meclofenamate (1 mug/ml) enhance contractile action of PGF2 alpha (5-20 mug) in guinea-pig tracheas superfused with Tyrode solution (5 ml/min). Unlike indomethacin, meclofenamate at a concentration of 10 mug/ml antagonizes contractions of guinea-pig tracheas produced by PGF2 alpha (5-20 mug), while the contractile action of histamine (0-5-2-0 mug) is enhanced. It is concluded that low concentrations of meclofenamate (1 mug/ml) inhibit prostaglandin biosynthesis in tracheal smooth muscles and therefore contractile action of exogenous PGF2 alpha is enhanced, while meclofenamate at a high concentration (10 mug/ml) blocks the receptor sites for PGF2 alpha.
D000818:Animals; D001665:Binding Sites / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D005260:Female; D006168:Guinea Pigs; D006632:Histamine / Q000494:pharmacology; D006634:Histamine H1 Antagonists / Q000494:pharmacology; D066298:In Vitro Techniques; D007213:Indomethacin / Q000008:administration & dosage / Q000494:pharmacology; D008297:Male; D008469:Meclofenamic Acid / Q000008:administration & dosage / Q000494:pharmacology*; D009119:Muscle Contraction / Q000187:drug effects*; D009130:Muscle, Smooth / Q000187:drug effects; D011453:Prostaglandins / Q000096:biosynthesis; D011460:Prostaglandins F / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D014132:Trachea / Q000187:drug effects; D062367:ortho-Aminobenzoates / Q000494:pharmacology*
D006634:Histamine H1 Antagonists; D011453:Prostaglandins; D011460:Prostaglandins F; D062367:ortho-Aminobenzoates; D008469:Meclofenamic Acid; D006632:Histamine; D007213:Indomethacin