Thromboxane-mimetic U46619 causes depressor responses in anaesthetized rats.
Intravenous (i.v.) or intra-arterial injections of U46619, a thromboxane A2 (TxA2)-mimetic agent, into chloralose-anaesthetized rats dose-dependently decreased the arterial blood pressure. Indomethacin (8 mg kg-1) or atropine (1 mg kg-1), given i.v. 30 min beforehand, attenuated the hypotensive effect of U46619 i.v. whereas methysergide pretreatment (5 mg kg-1 i.v.) was without action. Pretreatment with AH23848 (5 mg kg-1 i.v.), a specific TxA2-receptor antagonist, completely abolished the depressor responses to U46619. The findings suggest that the vasodepressor effect of U46619 appears to be mediated via TxA2-receptor activation, with the release of prostacyclin and/or acetylcholine both of which produce vasodilatation.
Department of Pharmacology, Faculty of Medicine, University of Hong Kong.
S G
SG
Hui
C W
CW
Ogle
D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D001713:Biphenyl Compounds / Q000494:pharmacology; D001794:Blood Pressure / Q000187:drug effects*; D004347:Drug Interactions; D007213:Indomethacin / Q000494:pharmacology; D007269:Injections, Intra-Arterial; D007275:Injections, Intravenous; D008297:Male; D008784:Methysergide / Q000494:pharmacology; D011450:Prostaglandin Endoperoxides, Synthetic / Q000008:administration & dosage* / Q000037:antagonists & inhibitors; D051381:Rats; D011919:Rats, Inbred Strains; D013931:Thromboxanes / Q000037:antagonists & inhibitors
D001713:Biphenyl Compounds; D011450:Prostaglandin Endoperoxides, Synthetic; D013931:Thromboxanes; D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; D001285:Atropine; C046926:AH 23848; D007213:Indomethacin; D008784:Methysergide