Levosimendan interacts with potassium channel blockers in human saphenous veins.
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)).
Höhn
József
J
Department of Surgery, Albert Szent-Györgyi Medical Center, University of Szeged, Hungary. hn@surg.szote.u-szeged.hu
Pataricza
János
J
Petri
András
A
Tóth
Gábor K
GK
Balogh
Adám
A
Varró
András
A
Papp
Julius Gy
JG
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*
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