Pinane thromboxane A2 analogues are non-selective prostanoid antagonists in rat and human stomach muscle.
1 Pinane thromboxane A2 (PTxA2) and its epi-OH isomer were studied on rat and human stomach longitudinal muscle. 2 PTxA2 (0.5 micrograms/ml) usually caused a slight contraction of rat gastric fundus. Contractions to PGE2, PGF2 alpha, PGI2 and epoxymethano analogues of PGH2 (U-46619 and U-44069) were substantially inhibited, whereas those to PGD2 and acetylcholine were only slightly reduced. 3 In human stomach, PTxA2 0.5 micrograms/ml rarely stimulated the muscle. Contractions to PGE2, PGF2 alpha and U-46619 were antagonized, with little effect on those to acetylcholine. 4 epi-PTxA2 (0.5 micrograms/ml) did not affect rat gastric tone. It was moderately potent against PGI2 on rat gastric fundus, but was less effective than PTxA2 against U-44069.
D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D000081008:Bicyclic Monoterpenes; D015237:Dinoprost; D011464:Epoprostenol / Q000494:pharmacology; D005260:Female; D006801:Humans; D008297:Male; D009130:Muscle, Smooth / Q000187:drug effects*; D011448:Prostaglandin Antagonists; D011453:Prostaglandins / Q000494:pharmacology; D011458:Prostaglandins E / Q000494:pharmacology; D011460:Prostaglandins F / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D013270:Stomach / Q000187:drug effects; D013928:Thromboxane A2 / Q000031:analogs & derivatives / Q000494:pharmacology*; D013931:Thromboxanes / Q000494:pharmacology*
D000081008:Bicyclic Monoterpenes; D011448:Prostaglandin Antagonists; D011453:Prostaglandins; D011458:Prostaglandins E; D011460:Prostaglandins F; D013931:Thromboxanes; D013928:Thromboxane A2; C020465:pinane-thromboxane A2; D015237:Dinoprost; D011464:Epoprostenol; D000109:Acetylcholine