5-Carboxamidotryptamine: a potent agonist mediating relaxation and elevation of cyclic AMP in the isolated neonatal porcine vena cava.
5-Carboxamidotryptamine (5-CT) caused concentration dependent relaxation of isolated rings from the porcine vena cava contracted with either prostaglandin F2 alpha, histamine or alpha-methyl 5-hydroxytryptamine. Relaxation was not inhibited by propranolol (l microM), atropine (1 microM), indomethacin (3 microM), mepyramine (1 microM), cimetidine (1 microM), or cocaine (10 microM). Methysergide, but not cyproheptadine, was a competitive antagonist of the relaxant effect of 5-CT with a pA2 value of 7.88. 5-Carboxamidotryptamine also increased the intracellular levels of cyclic AMP, an effect which was antagonised by methysergide (apparent pA2: 7.95) but not cyproheptadine. The alpha-methyl analogue of 5-hydroxytryptamine did not cause relaxation or elevate cyclic AMP. These results suggest that 5-CT causes relaxation and elevation of cyclic AMP by interaction with a specific 5-hydroxytryptamine receptor which is '5-HT1-like'.
M A
MA
Trevethick
W
W
Feniuk
P P
PP
Humphrey
D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D000818:Animals; D000831:Animals, Newborn; D001285:Atropine / Q000494:pharmacology; D002927:Cimetidine / Q000494:pharmacology; D003042:Cocaine / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism*; D015237:Dinoprost; D006632:Histamine / Q000494:pharmacology; D066298:In Vitro Techniques; D007213:Indomethacin / Q000494:pharmacology; D009119:Muscle Contraction / Q000187:drug effects*; D009126:Muscle Relaxation / Q000187:drug effects*; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000502:physiology*; D011433:Propranolol / Q000494:pharmacology; D011460:Prostaglandins F / Q000494:pharmacology; D011738:Pyrilamine / Q000494:pharmacology; D012701:Serotonin / Q000031:analogs & derivatives* / Q000494:pharmacology; D012702:Serotonin Antagonists; D013552:Swine; D014682:Vena Cava, Inferior / Q000187:drug effects / Q000502:physiology*
D011460:Prostaglandins F; D012702:Serotonin Antagonists; C042390:alpha-methylserotonin; D012701:Serotonin; D001285:Atropine; D002927:Cimetidine; D006632:Histamine; C047087:5-carboxamidotryptamine; D011433:Propranolol; D015237:Dinoprost; D000242:Cyclic AMP; D011738:Pyrilamine; D003042:Cocaine; D015056:1-Methyl-3-isobutylxanthine; D007213:Indomethacin