title: Direct vasoactive properties of thienopyridine-derived nitrosothiols.
abstract: Thienopyridines (ticlopidine, clopidogrel, and prasugrel) require in vivo metabolism to exhibit a critical thiol group in the active form that binds to the P2Y12 platelet receptor to inhibit platelet activation. We hypothesized that formation of thienopyridine-derived nitrosothiols (ticlopidine-SNO, clopidogrel-SNO, and prasugrel-SNO) occurs directly from the respective parent drug. Pharmaceutical-grade thienopyridine (ticlopidine, clopidogrel chloride, clopidogrel sulfate, clopidogrel besylate, or prasugrel) was added to nitrite in aqueous solution to form the respective thienopyridine-SNO (Th-SNO). An isolated aortic ring preparation was used to test vasoactivity of the Th-SNO derivatives. Increasing nitrite availability resulted in increased Th-SNO formation for all drugs (other than ticlopidine). Th-SNO induced significant endothelium-independent relaxation of preconstricted aortic rings. Clopidogrel-chloride-SNO displayed rapid-release kinetics in a chemical environment, which was reflected by immediate and transient vasorelaxation when compared with the SNO derivatives of the other thienopyridines. Accounting for differences in yield, clopidogrel-chloride-SNO exhibited the greatest propensity to immediately relax vascular tissue. Th-SNO derivatives exhibit nitrovasodilator properties by supplying NO that can directly activate vascular soluble guanylate cyclase to induce vasorelaxation. Differences in SNO yield and vasoactivity exist between thienopyridine preparations that might be important to our understanding of the direct pharmacological effectiveness of thienopyridines on vascular and platelet function.
authors.affiliation: Department of Cardiology and Department of Pharmacology and Toxicology (D.L), Wales Heart Research Institute, School of Medicine, Cardiff University, Cardiff, United Kingdom.
authors.forename: Shantu S
authors.initials: SS
authors.lastname: Bundhoo
authors.forename: Richard A
authors.initials: RA
authors.lastname: Anderson
authors.forename: Ewelina
authors.initials: E
authors.lastname: Sagan
authors.forename: Jessica
authors.initials: J
authors.lastname: Dada
authors.forename: Rebeca
authors.initials: R
authors.lastname: Harris
authors.forename: Julian P
authors.initials: JP
authors.lastname: Halcox
authors.forename: Derek
authors.initials: D
authors.lastname: Lang
authors.forename: Philip E
authors.initials: PE
authors.lastname: James
mesh_terms: D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects; D000077144:Clopidogrel; D005978:Glutathione / Q000031:analogs & derivatives / Q000494:pharmacology; D006162:Guanylate Cyclase / Q000037:antagonists & inhibitors; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D008163:Luminescent Measurements; D008297:Male; D013058:Mass Spectrometry; D015394:Molecular Structure; D009574:Nitro Compounds / Q000494:pharmacology; D010069:Oxadiazoles / Q000494:pharmacology; D010126:Ozone / Q000737:chemistry; D010879:Piperazines / Q000737:chemistry / Q000494:pharmacology; D000068799:Prasugrel Hydrochloride; D011810:Quinoxalines / Q000494:pharmacology; D011817:Rabbits; D026403:S-Nitrosothiols / Q000032:analysis / Q000737:chemistry / Q000494:pharmacology*; D012977:Sodium Nitrite / Q000737:chemistry / Q000494:pharmacology; D013056:Spectrophotometry, Ultraviolet; D058924:Thienopyridines / Q000737:chemistry / Q000494:pharmacology*; D013876:Thiophenes / Q000737:chemistry / Q000494:pharmacology; D013988:Ticlopidine / Q000031:analogs & derivatives / Q000737:chemistry / Q000494:pharmacology; D014664:Vasodilation / Q000187:drug effects; D014665:Vasodilator Agents / Q000737:chemistry / Q000494:pharmacology*
chemical_list: C095284:1H-(1,2,4)oxadiazolo(4,3-a)quinoxalin-1-one; D009574:Nitro Compounds; D010069:Oxadiazoles; D010879:Piperazines; D011810:Quinoxalines; D026403:S-Nitrosothiols; C116027:S-nitroglutathione; D058924:Thienopyridines; D013876:Thiophenes; D014665:Vasodilator Agents; D010126:Ozone; D000077144:Clopidogrel; D006162:Guanylate Cyclase; D000068799:Prasugrel Hydrochloride; D005978:Glutathione; D012977:Sodium Nitrite; D013988:Ticlopidine