Inhibition by suprofen and other non-narcotic analgesic drugs of the effects of prostaglandin precursor on isolated tissues and platelets

Abstract

Contractions caused by Slow Reacting Substance C(SRS-C) and by Arachidonic Acid hydroperoxide (AAP) in the guinea-pig ileum and by AAP in the rat fundus were studied in the presence of suprofen and of 3 reference compounds. The dose-related inhibitions were not due to antagonism of prostaglandins. Other agonists of gastrointestinal smooth muscle were not or only weakly antagonized. For the study of selective inhibition of AAP-induced contractions by non-narcotic analgesics, the rat fundus is the preferred preparation. In this model suprofen had an ED50 of 1.27 x 10(-7) M (0.033 mug/ml), being 1.5, 94 and 2, 020 times more potent than indomethacin, phenybutazone and acetylsalicylic acid, respectively. Suprofen also strongly inhibited malondialdehyde formation by guinea-pig platelets incubated with arachidonic acid. The reported effects point to inhibition by suprofen of prostaglandin biosynthesis. The antagonism of AAP-induced contractions in the rat fundus is a valuable test system for inhibitors of prostaglandin biosynthesis.