Visualization and functional characterization of the developing murine cardiac conduction system

• DOI: 10.1242/dev.128.10.1785
• Publication Date: 2021-04-23T20:03:28Z
• Authors: Stacey Rentschler; Dhananjay M. Vaidya; Houman Tamaddon; Karl Degenhardt; David Sassoon; Gregory E. Morley; José Jalife; Glenn I. Fishman
• Keywords: Purkinje fibers; Optical mapping; Heart development; Embryonic heart

ABSTRACT The cardiac conduction system is a complex network of cells that together orchestrate the rhythmic and coordinated depolarization heart. molecular mechanisms regulating specification patterning form this conductive are largely unknown. Studies in avian models have suggested components arise from progressive recruitment cardiomyogenic progenitors, potentially influenced by inductive effects neighboring coronary vasculature. However, relatively little known about process development mammalian species, especially mouse, where even histological identification remains problematic. We identified line transgenic mice lacZ reporter gene expression delineates developing mature murine system, extending proximally sinoatrial node to distal Purkinje fibers. Optical mapping electrical activity using voltage-sensitive dye confirms indeed specialized system. Analysis during sequential stages cardiogenesis provides detailed view maturation demonstrates occurs surprisingly early embryogenesis. Moreover, optical studies embryonic hearts demonstrate His-Purkinje functioning well before septation has completed. Thus, these describe novel marker identifies throughout development. data highlight important differences between Finally, tool for exploring circuitry controlling should be invaluable developmental mutants with potential structural or functional defects.