Presence of functional sarcoplasmic reticulum in the developing heart and its confinement to chamber myocardium
| Autor: | M. J. B. Van Den Hoff, Jan W.T. Fiolet, Frank Wuytack, J M Lamers, Jaco Hagoort, Vincent M. Christoffels, Gerry T.M. Wagenaar, A. F. M. Moorman, P. A. J. De Boer, K Bezstarosti, Cees A. Schumacher |
|---|---|
| Přispěvatelé: | Biochemistry, Other departments |
| Rok vydání: | 2000 |
| Předmět: |
Cardiac function curve
medicine.medical_specialty sarco(endo)plasmic reticulum Ca2+ pump Heart Ventricles chicken cardiac development Calcium-Transporting ATPases Chick Embryo In situ hybridization Biology Sarcoplasmic Reticulum Calcium-Transporting ATPases Tetracaine Internal medicine Image Processing Computer-Assisted Morphogenesis medicine Animals Humans Tissue Distribution rat Calcium Signaling Heart Atria human Molecular Biology Calcium signaling Ryanodine Ryanodine receptor Myocardium Endoplasmic reticulum Heart Cell Biology Immunohistochemistry Rats Models Structural Sarcoplasmic Reticulum Endocrinology Verapamil Cardiac chamber cardiovascular system Atrioventricular canal medicine.drug Developmental Biology |
| Zdroj: | Developmental Biology, 223, 279-290. Elsevier Inc. Developmental biology, 223(2), 279-290. Academic Press Inc. |
| ISSN: | 1095-564X 0012-1606 |
| Popis: | During development fast-contracting atrial and ventricular chambers develop from a peristaltic-contracting heart tube. This study addresses the question of whether chamber formation is paralleled by a matching expression of the sarcoplasmic reticulum (SR) Ca(2+) pump. We studied indo-1 Ca(2+) transients elicited by field stimulation of linear heart tube stages and of explants from atria and outflow tracts of the prototypical preseptational E13 rat heart. Ca(2+) transients of H/H 11+ chicken hearts, which constitute the prototypic linear heart tube stage, were sensitive to verapamil only, indicating a minor contribution of Ca(2+)-triggered SR Ca(2+) release. Outflow tract transients displayed sensitivity to the inhibitors similar to that of the linear heart tube stages. Atrial Ca(2+) transients disappeared upon addition of ryanodine, tetracaine, or verapamil, indicating the presence of Ca(2+)-triggered SR Ca(2+) release. Quantitative radioactive in situ hybridization on sections of E13 rat hearts showed approximately 10-fold higher SERCA2a mRNA levels in the atria compared to nonmyocardial tissue and approximately 5-fold higher expression in compact ventricular myocardium. The myocardium of atrioventricular canal, outflow tract, inner curvature, and ventricular trabecules displayed weak expression. Immunohistochemistry on sections of rat and human embryos showed a similar pattern. The significance of these findings is threefold. (i) A functional SR is present long before birth. (ii) SR development is concomitant with cardiac chamber development, explaining regional differences in cardiac function. (iii) The pattern of SERCA2a expression underscores a manner of chamber development by differentiation at the outer curvature, rather than by segmentation of the linear heart tube. |
| Databáze: | OpenAIRE |
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