title: Levosimendan interacts with potassium channel blockers in human saphenous veins.
abstract: The involvement of potassium channels in the venodilating capacity of the inodilator levosimendan in human saphenous vein preparations was investigated. Levosimendan caused relaxation with 50% effective concentration (EC50) of 0.32 +/- 0.04 microM in isolated veins contracted by 5-hydroxytryptamine. Fifteen microM glibenclamide, a blocker of the ATP-sensitive potassium channels (K(ATP)), partially inhibited the relaxing effect of the inodilator. In the presence of iberiotoxin, the selective blocker of large conductance calcium-activated potassium channels (BK(Ca)), levosimendan induced contraction with EC50 of 0.21 +/- 0.06 microM. We presume that levosimendan dilates human saphenous veins by interacting with hyperpolarizing potassium channels (K(ATP) and BK(Ca)).
authors.affiliation: Department of Surgery, Albert Szent-Györgyi Medical Center, University of Szeged, Hungary. hn@surg.szote.u-szeged.hu
authors.forename: József
authors.initials: J
authors.lastname: Höhn
authors.forename: János
authors.initials: J
authors.lastname: Pataricza
authors.forename: András
authors.initials: A
authors.lastname: Petri
authors.forename: Gábor K
authors.initials: GK
authors.lastname: Tóth
authors.forename: Adám
authors.initials: A
authors.lastname: Balogh
authors.forename: András
authors.initials: A
authors.lastname: Varró
authors.forename: Julius Gy
authors.initials: JG
authors.lastname: Papp
mesh_terms: D004347:Drug Interactions; D005905:Glyburide / Q000494:pharmacology; D006801:Humans; D006835:Hydrazones / Q000494:pharmacology*; D066298:In Vitro Techniques; D010455:Peptides / Q000494:pharmacology; D026902:Potassium Channel Blockers / Q000494:pharmacology*; D015221:Potassium Channels / Q000187:drug effects* / Q000502:physiology; D024681:Potassium Channels, Calcium-Activated / Q000187:drug effects / Q000502:physiology; D011724:Pyridazines / Q000494:pharmacology*; D012501:Saphenous Vein / Q000187:drug effects* / Q000502:physiology; D012701:Serotonin; D000077464:Simendan; D014664:Vasodilation / Q000187:drug effects* / Q000502:physiology; D014665:Vasodilator Agents / Q000494:pharmacology*
chemical_list: D006835:Hydrazones; D010455:Peptides; D026902:Potassium Channel Blockers; D015221:Potassium Channels; D024681:Potassium Channels, Calcium-Activated; D011724:Pyridazines; D014665:Vasodilator Agents; D012701:Serotonin; D000077464:Simendan; C064719:iberiotoxin; D005905:Glyburide