Atrium-specific ion channels in the zebrafishA role of I-KACh in atrial repolarization

作者：Skarsfeldt M A; Bomholtz S H; Lundegaard P R; Lopez Izquierdo A; Tristani Firouzi M; Bentzen B H^*

来源：Acta Physiologica, 2018, 223(3): UNSP e13049.

DOI：10.1111/apha.13049

• action potential
• atrium
• ECG
• heart
• ion channel
• zebrafish

AimThe zebrafish has emerged as a novel model for investigating cardiac physiology and pathology. The aim of this study was to investigate the atrium-specific ion channels responsible for shaping the atrial cardiac action potential in zebrafish.
MethodsUsing quantitative polymerase chain reaction, we assessed the expression level of atrium-specific potassium channels. The functional role of these channels was studied by patch clamp experiments on isolated atrial and ventricular cardiomyocytes and by optical mapping of explanted adult zebrafish hearts. Finally, surface ECGs were recorded to establish possible invivo roles of atrial ion channels.
ResultsIn isolated adult zebrafish hearts, we identified the expression of kcnk3, kcnk9, kcnn1, kcnn2, kcnn3, kcnj3 and kcnj5, the genes that encode the atrium-specific K-2P, K(Ca)2.x and K(ir)3.1/4 (K-ACh) ion channels. The electrophysiological data indicate that the acetylcholine-activated inward-rectifying current, I-KACh,I- plays a major role in the zebrafish atrium, whereas K(2P)3.1/9.1 and K(Ca)2.x channels do not appear to be involved in regulating the action potential in the zebrafish heart.
ConclusionWe demonstrate that the acetylcholine-activated inward-rectifying current (I-KACh) current plays a major role in the zebrafish atrium and that the zebrafish could potentially be a cost-effective and reliable model for pharmacological testing of atrium-specific I-KACh modulating compounds.

• 出版日期2018-7