title: Receptor-mediated stimulation of aortic prostacyclin release by 5-hydroxytryptamine.
abstract: 5-Hydroxytryptamine (5-HT) stimulated prostacyclin release, measured by radioimmunoassay as 6-keto-prostaglandin F1 alpha, from rat aorta in a dose-dependent manner (3 X 10(-7)-10(-4) M). A statistically significant stimulation was observed at concentrations higher than 3 X 10(-6) M. Norepinephrine also increased prostacyclin release but only at a high concentration (10(-4) M) and histamine (3 X 10(-5) and 10(-4) M) had no significant effect. Among some structurally 5-HT-related analogues, only tryptamine exhibited a dose-dependent stimulatory effect on prostacyclin release but it was slightly less potent than 5-HT. Tryptophan and 5-hydroxytryptophan had no effects whereas 5-hydroxyindoleacetic acid at 10(-4) M stimulated slightly. Prostacyclin release stimulated by 5-HT was depressed by non-specific 5-HT antagonists, methysergide, mianserin and cyproheptadine. In contrast, a specific 5-HT2 antagonist ketanserin (3 X 10(-7)-10(-5) M) had no antagonistic effect. These results suggest that 5-HT stimulates the release of prostacyclin from rat aorta by interaction with receptors distinct from its 5-HT2 subtype.
mesh_terms: D000818:Animals; D001013:Aorta, Thoracic / Q000378:metabolism; D011464:Epoprostenol / Q000378:metabolism*; D066298:In Vitro Techniques; D008297:Male; D009638:Norepinephrine / Q000494:pharmacology; D011451:Prostaglandin-Endoperoxide Synthases / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D011985:Receptors, Serotonin / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D012701:Serotonin / Q000031:analogs & derivatives / Q000494:pharmacology*; D013928:Thromboxane A2 / Q000494:pharmacology
chemical_list: D011985:Receptors, Serotonin; D012701:Serotonin; D013928:Thromboxane A2; D011464:Epoprostenol; D011451:Prostaglandin-Endoperoxide Synthases; D009638:Norepinephrine