title: Effect of diadenosine phosphates on human umbilical vessels: novel platelet-derived vasoconstrictors.
abstract: The responses of human isolated umbilical artery to the novel platelet-derived mediators, diadenosine phosphates, P1,P5-di(adenosine-5')pentaphosphate (AP5A) and P1,P6-di(adenosine-5')hexaphosphate (AP6A) were studied in vitro. AP5A (1 nM-300 microM; n = 7) and AP6A (1 nM-30 microM; n = 5) produced transient concentration-dependent contractions. Responses to AP5A were unaffected by co-incubation with indomethacin (10 microM; n = 4), NGmonomethyl-L-arginine (L-NMMA; 300 microM; n = 4) and theophylline (1 microM; n = 5). These results demonstrate that diadenosine phosphates have constrictor effects on human blood vessels in vitro and are consistent with a role for these platelet-derived mediators in the regulation of blood vessel tone.
authors.affiliation: Department of Pharmacology and Clinical Pharmacology, St George's Hospital Medical School, London, UK.
authors.forename: G
authors.initials: G
authors.lastname: Davies
authors.forename: R J
authors.initials: RJ
authors.lastname: MacAllister
authors.forename: R G
authors.initials: RG
authors.lastname: Bogle
authors.forename: P
authors.initials: P
authors.lastname: Vallance
mesh_terms: D001120:Arginine / Q000031:analogs & derivatives / Q000494:pharmacology; D001792:Blood Platelets / Q000187:drug effects; D015226:Dinucleoside Phosphates / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D066298:In Vitro Techniques; D007213:Indomethacin / Q000494:pharmacology; D009119:Muscle Contraction / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D013806:Theophylline / Q000494:pharmacology; D014469:Umbilical Arteries / Q000187:drug effects*; D014662:Vasoconstrictor Agents / Q000494:pharmacology*; D019323:omega-N-Methylarginine
chemical_list: D015226:Dinucleoside Phosphates; D004791:Enzyme Inhibitors; D014662:Vasoconstrictor Agents; D019323:omega-N-Methylarginine; C012275:P(1),P(5)-di(adenosine-5'-)pentaphosphate; C070070:diadenosine 5',5''''-P1,P6-hexaphosphate; D001120:Arginine; D013806:Theophylline; D007213:Indomethacin