Block of Na+/Ca2+ exchanger by SEA0400 in human right atrial preparations from patients in sinus rhythm and in atrial fibrillation

The Na+/Ca2+ exchanger (NCX) plays a major role in myocardial Ca2+ homoeostasis, but is also considered to contribute to the electrical instability and contractile dysfunction in chronic atrial fibrillation (AF). Here we have investigated the effects of the selective NCX blocker SEA0400 in human rig...

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Elmentve itt :
Bibliográfiai részletek
Szerzők: Christ Torsten
Kovács Péter P.
Acsai Károly
Knaut Michael
Eschenhagen Thomas
Jost Norbert László
Varró András
Wettwer Erich
Ravens Ursula
Dokumentumtípus: Cikk
Megjelent: 2016
Sorozat:EUROPEAN JOURNAL OF PHARMACOLOGY 788
doi:10.1016/j.ejphar.2016.06.050

mtmt:3095415
Online Access:http://publicatio.bibl.u-szeged.hu/15890
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520 3 |a The Na+/Ca2+ exchanger (NCX) plays a major role in myocardial Ca2+ homoeostasis, but is also considered to contribute to the electrical instability and contractile dysfunction in chronic atrial fibrillation (AF). Here we have investigated the effects of the selective NCX blocker SEA0400 in human right atrial cardiomyocytes from patients in sinus rhythm (SR) and AF in order to obtain electrophysiological evidence for putative antiarrhythmic activity of this new class of drugs. Action potentials were measured in right atrial trabeculae using conventional microelectrodes. Human myocytes were enzymatically isolated. Rat atrial and ventricular cardiomyocytes were used for comparison. Using perforated-patch, NCX was measured as Ni2+-sensitive current during ramp pulses. In ruptured-patch experiments, NCX current was activated by changing the extracellular Ca2+ concentration from 0 to 1mM in Na+-free bath solution (100mM Na+ intracellular, "Hilgemann protocol"). Although SEA0400 was effective in rat cardiomyocytes, 10microM did not influence action potentials and contractility, neither in SR nor AF. SEA0400 (10muM) also failed to affect human atrial NCX current measured with perforated patch. With the "Hilgemann protocol" SEA0400 concentration-dependently suppressed human atrial NCX current, and its amplitude was larger in AF than in SR cardiomyocytes. Our results confirm higher NCX activity in AF than SR. SEA0400 fails to block Ni2+-sensitive current in human atrial cells unless unphysiological conditions are used. We speculate that block of NCX with SEA0400 depends on intracellular Na+ concentration. 
700 0 1 |a Kovács Péter P.  |e aut 
700 0 1 |a Acsai Károly  |e aut 
700 0 1 |a Knaut Michael  |e aut 
700 0 1 |a Eschenhagen Thomas  |e aut 
700 0 1 |a Jost Norbert László  |e aut 
700 0 1 |a Varró András  |e aut 
700 0 1 |a Wettwer Erich  |e aut 
700 0 1 |a Ravens Ursula  |e aut 
856 4 0 |u http://publicatio.bibl.u-szeged.hu/15890/1/ChristEurJPHarmacol2016.pdf  |z Dokumentum-elérés