Vasorelaxant and platelet-suppressant potencies of four NO-donors.
Rabbit aortic strips were arranged in a Vane's cascade and superfused with Krebs buffer which contained phenylephrine hydrochloride (100 nM) and indomethacin (5 microM). EC50 (nM) for vasorelaxant action of NO-donors on rabbit aortic strips were as follows: glyceryl trinitrate--64.0, sodium nitroprusside--124.5, S-nitroso-N-acetylpenicillamine--305.7, SIN-1 (metabolite of molsidomine)--510.0. On the other hand IC50 (microM) for antiaggregatory action of NO-donors in human platelet rich plasma aggregated with threshold concentrations of collagen (0.5-1 micrograms/ml) were as follows: S-nitroso-N-acetylpenicillamine--7,1, SIN-1--13.6, sodium nitroprusside--28.0. Glyceryl trinitrate did not inhibit platelet aggregation at concentrations up to 1 mM. Sodium nitroprusside was more specific (EC50/IC50 = 0.0043) than SNAP and SIN-1 (EC50/IC50 = 0.043 and 0.037, respectively) as a vasorelaxant than as a platelet suppressant. Thus relative potencies of four c-GMP stimulants as vasorelaxants and platelet-suppressants differed considerably and several possible explanations for these differences were put forward.
Zembowicz
A
A
Department of Pharmacology, N. Copernicus Academy of Medicine, Cracow, Poland.
Dudek
R D
RD
Radziszewski
W
W
Swierkosz
T A
TA
Trybulec
M
M
Gryglewski
R J
RJ
D000818:Animals; D001011:Aorta / Q000187:drug effects; D006801:Humans; D066298:In Vitro Techniques; D008981:Molsidomine / Q000031:analogs & derivatives / Q000494:pharmacology; D009569:Nitric Oxide / Q000378:metabolism*; D005996:Nitroglycerin / Q000494:pharmacology; D009599:Nitroprusside / Q000494:pharmacology; D010396:Penicillamine / Q000031:analogs & derivatives / Q000494:pharmacology; D010975:Platelet Aggregation Inhibitors; D011817:Rabbits; D026423:S-Nitroso-N-Acetylpenicillamine; D014665:Vasodilator Agents
D010975:Platelet Aggregation Inhibitors; D014665:Vasodilator Agents; D009599:Nitroprusside; D009569:Nitric Oxide; C002385:linsidomine; D026423:S-Nitroso-N-Acetylpenicillamine; D008981:Molsidomine; D005996:Nitroglycerin; D010396:Penicillamine