Further characterization of the contraction-mediating prostanoid receptors in feline cerebral arteries. Effects of the thromboxane-receptor antagonist AH 23848.
The effects of the thromboxane-receptor antagonist AH 23848 were investigated on isolated feline basilar arteries (BA). AH 23848 (10(-6) mol l-1) had no effect on contractions induced by 5-hydroxytryptamine or potassium, whereas the drug (10(-8)-10(-6) mol l-1) induced a parallel shift to the right in contractions induced by the thromboxane A2 mimic U46619. There was no depression of the maximum contraction, indicating competitive antagonism. The Schild plot revealed a slope index of unity with a pA2 value of 8.46. In contrast, 10(-6) mol l-1 AH 23848 depressed the maximum PGF2 alpha-induced contraction significantly from 100% to 13%. U46619 was able to induce a contraction amounting to 98% if the drug was added on top of the PGF2 alpha-induced contraction in the presence of 10(-6) mol l-1 AH 23848. The results provide strong support for previous suggestions that prostanoid-induced contractions in the feline BA are mediated by two receptor subtypes, one of which can be classified as a thromboxane-sensitive (TP) receptor.
Uski
T K
TK
Department of Clinical Pharmacology, Lund University Hospital, Sweden.
D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; D000818:Animals; D001488:Basilar Artery / Q000187:drug effects*; D001713:Biphenyl Compounds / Q000494:pharmacology*; D002415:Cats; D015237:Dinoprost / Q000494:pharmacology; D009119:Muscle Contraction / Q000187:drug effects*; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D011188:Potassium / Q000494:pharmacology; D011450:Prostaglandin Endoperoxides, Synthetic / Q000494:pharmacology; D011982:Receptors, Prostaglandin / Q000187:drug effects*; D017482:Receptors, Thromboxane; D012701:Serotonin / Q000494:pharmacology
D001713:Biphenyl Compounds; D011450:Prostaglandin Endoperoxides, Synthetic; D011982:Receptors, Prostaglandin; D017482:Receptors, Thromboxane; D012701:Serotonin; D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; C046926:AH 23848; D015237:Dinoprost; D011188:Potassium