The susceptibility of the rat pulmonary and caval vein myocardium to the catecholamine‐induced ectopy changes oppositely in postnatal development

Key points The developmental changes of the caval (SVC) and pulmonary vein (PV) myocardium electrophysiology are traced throughout postnatal ontogenesis. in SVC as well PV demonstrate age-dependent differences ability to maintain resting membrane potential, manifest automaticity a form ectopic action potentials basal condition responses adrenergic stimulation. Electrophysiological characteristics two distinct types thoracic change an opposite manner during early ontogenesis with increased proarrhythmicity decreased veins. Predisposition cardiac tissue proarrhythmycity develops time correlation establishment sympathetic innervation tissue. electrophysiological properties shift from pacemaker-like phenotype atrial accompaniment nerve growth receptor expression changes. Abstract is considered main source for fibrillation initiation due its high susceptibility activity. mechanism by which when superior vena cava became proarrhythmic still unknown. In this study, we distribution reveal occurrence myocardium. A standard microelectrode technique was used assess potential (RMP), generate spontaneous (SAP) adrenergically induced ectopy multicellular preparations rats different ages. Immunofluorescence imaging trace innervation, β1- α1A-adrenergic (AR) distribution. We revealed that SAP stimulation While decreases age myocardium, it significantly increases starts RMP instability activity 14th day life correlates appearance addition, attenuation occurs concomitantly increase β1-ARs, but not α1A-AR levels. Our results support contention development, resulting higher adults.