نتایج جستجو برای: epicardium
تعداد نتایج: 1451 فیلتر نتایج به سال:
Recent studies have shown that canine ventricular epicardium and endocardium differ with respect to electrophysiological characteristics and pharmacological responsiveness and that these differences are in large part due to the presence of a prominent transient outward current Ito and a spike-and-dome morphology of the action potential in epicardium but not endocardium. In attempting to quantit...
To determine whether canine epicardium and endocardium show intrinsically different electrophysiological responses to metabolic alterations that occur during acute myocardial ischemia in vivo, endocardial, epicardial, papillary muscle tip, and Purkinje fibers (PF) were superfused in vitro with Tyrode's solution containing 8.0 DM KC1 at a pH of 6.85 and a Po2 < 50 mm Hg. During the initial 10 mi...
The epicardium makes essential cellular and paracrine contributions to the growth of the fetal myocardium and the formation of the coronary vasculature. However, whether the epicardium has similar roles postnatally in the normal and injured heart remains enigmatic. Here, we have investigated this question using genetic fate-mapping approaches in mice. In uninjured postnatal heart, epicardial ce...
In contrast to lower vertebrates, the mammalian heart has a very limited regenerative capacity. Cardiomyocytes, lost after ischemia, are replaced by fibroblasts. Although the human heart is able to form new cardiomyocytes throughout its lifespan, the efficiency of this phenomenon is not enough to substitute sufficient myocardial mass after an infarction. In contrast, zebrafish hearts regenerate...
The existence of the epicardial telocytes was previously documented by immunohistochemistry (IHC) or immunofluorescence. We have also demonstrated recently that telocytes are present in mice epicardium, within the cardiac stem-cell niches, and, possibly, they are acting as nurse cells for the cardiomyocyte progenitors. The rationale of this study was to show that telocytes do exist in human (su...
The epicardium, the tissue layer covering the cardiac muscle (myocardium), develops from the proepicardium, a mass of coelomic progenitors located at the venous pole of the embryonic heart. Proepicardium cells attach to and spread over the myocardium to form the primitive epicardial epithelium. The epicardium subsequently undergoes an epithelial-to-mesenchymal transition to give rise to a popul...
The epicardium is the primary source of coronary vascular smooth muscle cells (cVSMCs) and fibroblasts that reside in the compact myocardium. To form these epicardial-derived cells (EPDCs), the epicardium undergoes the process of epithelial to mesenchymal transition (EMT). Although several signaling pathways have been identified that disrupt EMT, no pathway has been reported that restricts this...
The epicardium plays an essential role in coronary artery formation and myocardial development. However, signals controlling the developing epicardium and epicardial-mesenchymal transition (EMT) in the normal and diseased adult heart are studied less rigorously. Here we investigated the role of angiogenic hormone, prokineticin-2 and its receptor PKR1 in the epicardium of developing and adult he...
The epicardium has recently been identified as an active and essential element of cardiac development. Recent reports have unveiled a variety of functions performed by the embryonic epicardium, as well as the cellular and molecular mechanisms regulating them. However, despite its developmental importance, a number of unsolved issues related to embryonic epicardial biology persist. In this revie...
BACKGROUND We recently reported that sodium channel block can produce opposite effects on action potential duration (APD) and refractoriness in epicardial versus endocardial tissues of the canine ventricle. In addition, strong sodium channel current inhibition was found to cause loss of the action potential dome in epicardium but not endocardium, thus inducing a marked dispersion of repolarizat...
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