Alday Aintzane, Alonso Hiart, Gallego Monica, Urrutia Janire, Letamendia Ainhoa, Callol Carles, Casis Oscar
Department of Physiology, School of Pharmacy, University of the Basque Country UPV/EHU, Spain.
Department of Physiology, School of Pharmacy, University of the Basque Country UPV/EHU, Spain; Lascaray Research Center, University of the Basque Country UPV/EHU, Spain.
Pharmacol Res. 2014 Jun;84:26-31. doi: 10.1016/j.phrs.2014.03.011. Epub 2014 Apr 18.
Over the last years zebrafish has become a popular model in the study of cardiac physiology, pathology and pharmacology. Recently, the application of the 3Rs regulation and the characteristics of the embryo have reduced the use of adult zebrafish use in many studies. However, the zebrafish embryo cardiac physiology is poorly characterized since most works have used indirect techniques and direct recordings of cardiac action potential and ionic currents are scarce. In order to optimize the zebrafish embryo model, we used electrophysiological, pharmacological and immunofluorescence tools to identify the characteristics and the ionic channels involved in the ventricular action potentials of zebrafish embryos. The application of Na(+) or T-type Ca(+2) channel blockers eliminated the cardiac electrical activity, indicating that the action potential upstroke depends on Na(+) and T-type Ca(+2) currents. The plateau phase depends on L-type Ca(+2) channels since it is abolished by specific blockade. The direct channel blockade indicates that the action potential repolarization and diastolic potential depends on ERG K(+) channels. The presence in the embryonic heart of the Nav1.5, Cav1.2, Cav3.2 and ERG channels was also confirmed by immunofluorescence, while the absence of effect of specific blockers and immunostaining indicate that two K(+) repolarizing currents present in human heart, Ito and IKs, are absent in the embryonic zebrafish heart. Our results describe the ionic channels present and its role in the zebrafish embryo heart and support the use of zebrafish embryos to study human diseases and their use for drug testing.
在过去几年中，斑马鱼已成为心脏生理学、病理学和药理学研究中的一种流行模型。最近，3R 原则的应用以及胚胎的特性减少了许多研究中成年斑马鱼的使用。然而，斑马鱼胚胎心脏生理学的特征尚不明确，因为大多数研究使用的是间接技术，而心脏动作电位和离子电流的直接记录很少。为了优化斑马鱼胚胎模型，我们使用电生理学、药理学和免疫荧光工具来确定斑马鱼胚胎心室动作电位所涉及的特征和离子通道。应用钠（Na⁺）或 T 型钙（Ca²⁺）通道阻滞剂可消除心脏电活动，表明动作电位的上升依赖于 Na⁺和 T 型 Ca²⁺电流。平台期依赖于 L 型 Ca²⁺通道，因为它会被特异性阻断所消除。直接通道阻断表明动作电位复极化和舒张电位依赖于 ERG K⁺通道。免疫荧光也证实了胚胎心脏中存在 Nav1.5、Cav1.2、Cav3.2 和 ERG 通道，而特异性阻滞剂和免疫染色无作用表明人类心脏中存在的两种 K⁺复极化电流 Ito 和 IKs 在斑马鱼胚胎心脏中不存在。我们的结果描述了斑马鱼胚胎心脏中存在的离子通道及其作用，并支持使用斑马鱼胚胎来研究人类疾病及其在药物测试中的应用。
