Serum-free, chemically defined medium to evaluate the direct effects of growth factors and inhibitors on proliferation and function of neonatal rat cardiac muscle cells in culture

1989 ◽  
Vol 25 (7) ◽  
pp. 601-606 ◽  
Author(s):  
Takahiko Suzuki ◽  
Miyuki Ohta ◽  
Hiroyoshi Hoshi
Keyword(s):  
Growth Factors ◽  
Cardiac Muscle ◽  
Muscle Cells ◽  
Defined Medium ◽  
Neonatal Rat ◽  
Chemically Defined Medium ◽  
Direct Effects ◽  
Cardiac Muscle Cells ◽  
Serum Free ◽  
And Function

scholarly journals Structure of myofibrils at extra-junctional membrane attachment sites in cultured cardiac muscle cells

1988 ◽  
Vol 89 (1) ◽  
pp. 97-106
Author(s):  
B.T. Atherton ◽  
M.M. Behnke
Keyword(s):  
Cell Membrane ◽  
Cardiac Muscle ◽  
Muscle Cells ◽  
Neonatal Rat ◽  
Heart Cells ◽  
Cardiac Muscle Cells ◽  
Lateral Contact ◽  
Attachment Sites ◽  
Membrane Attachment ◽  
Actin Cables

The composition and organization of myofibrils at extra-junctional membrane attachment sites in cultured neonatal rat cardiac muscle cells were analysed by immunofluorescence and electron microscopy. When myofibril terminals attached to the cell membrane via focal contacts at regions of the sarcolemma that lacked intercalated discs, they appeared to be non-striated and resembled thick actin cables. Although the non-striated terminals contained actin, myosin and alpha-actinin, the proteins were not organized into recognizable sarcomeres at the light microscopic level. Analysis of the structure of the terminals in the electron microscope confirmed that the usual sarcomeric organization and attachments to the sarcolemma were markedly modified. The non-striated myofibril terminals differed in structure from both stress fibres in non-muscle cells and stress fibre-like structures present in embryonic heart cells in culture. Non-striated myofibril terminals attached to the cell membrane by lateral contact with extra-junctional electron-dense membrane plaques rather than by insertion by their ends into the fascia adherens. It is proposed that the structure and composition of membrane-attachment points for myofibrils may have an influence on the structure, organization or stability of contractile elements in cardiac muscle.

Effects of hypoxia on cardiac growth in neonatal rat

1976 ◽  
Vol 231 (5) ◽  
pp. 1445-1450 ◽  
Author(s):  
M Hollenberg ◽  
N Honbo ◽  
AJ Samorodin
Keyword(s):  
Body Weight ◽  
Left Ventricle ◽  
Cardiac Muscle ◽  
Neonatal Period ◽  
Vascular Endothelial Cells ◽  
Muscle Cells ◽  
Left Ventricular ◽  
Neonatal Rat ◽  
Low Oxygen ◽  
Cardiac Muscle Cells

To determine whether low oxygen environments enhance cardiac cell division in the neonatal period, newborn rat pups were reared for 21 days in 12-15% oxygen. Left ventricle and right ventricle weights were 30 and 180% greater than controls matched for body weight (P less than 0.001) as were left ventricle/body weight ratios (3.68+/-0.26 vs. 2.99+/-0.05 mg LV/g body wt,P less than 0.001). Left ventricular total DNA and DNA concentration was 95 and 48% greater than controls (P less than 0.001). Autoradiography confirmed that this increase in ventricular DNA resulted from an increased rate of division of cardiac muscle cells, fibroblast, and vascular endothelial cells. When [3H]thymidine was injected on day ), autoradiographs prepared on day 21 reflected an increased dilution of label in hypoxic rats consistent with enhanced proliferation. The labeling index and grains per nucleus of ventricular muscle cells was 25% (P less than 0.01) and 20% (P less than 0.02) less than controls, Thus, hypoxic stress applied early in the neonatal period augments the rate of division and ultimate number of cardiac muscle cells. Whether this enhancement results from a primary effect of oxygen or from secondary hemodynamic factors remains unknown.

Two nuclei inside a single cardiac muscle cell. More questions than answers about the binucleation of cardiomyocytes

Biologia ◽  
2017 ◽  
Vol 72 (8) ◽  
Author(s):  
Michal Miko ◽  
Jan Kyselovic ◽  
Lubos Danisovic ◽  
Tomas Barczi ◽  
Stefan Polak ◽  
...  
Keyword(s):  
Cardiac Muscle ◽  
Muscle Cells ◽  
Prenatal Development ◽  
The Body ◽  
Cardiac Muscle Cells ◽  
Physiological Importance ◽  
Neonatal Life ◽  
Proliferation Activity ◽  
Cell Shaping ◽  
And Function

AbstractHuman cardiac muscle cells are the most physically energetic cells in the body, and according to various researchers they contain two nuclei in 25–40%. In humans, the heart during prenatal development consists mainly of cardiomyocytes with one nucleus. Just before birth, binucleation begins and can extend into early neonatal life. The physiological importance of binucleation is still poorly understood. In this critical review, we provide a summary of the latest research on binucleation of cardiac muscle cells, with special emphasis on the potential application of such knowledge to the fields of regenerative medicine. We summed up and discussed about ten possible biological arguments why binucleation may be beneficial for cardiac muscle cells as well as for the whole myocardium. These arguments include increase of gene expression, purposeful cell shaping, increase of metabolic activity, energy-saving growth and function, need for organ growth despite of telomere depletion, adaptation to stress (tissue regeneration), prevention of overgrowth – organ shaping, prevention of aneuploidy, terminally differentiated state (cardiomyocytes exit the cell cycle, end of proliferation activity); or, we hypothesize, binucleation is just an unwanted side product.

Translation of heart preproenkephalin mRNA and secretion of enkephalin peptides from cultured cardiac myocytes

1992 ◽  
Vol 263 (5) ◽  
pp. H1560-H1566 ◽  
Author(s):  
J. P. Springhorn ◽  
W. C. Claycomb
Keyword(s):  
Cardiac Muscle ◽  
Muscle Cells ◽  
Neonatal Rat ◽  
Ribonuclease Protection Assay ◽  
Cardiac Muscle Cells ◽  
Adult Rat ◽  
Rabbit Reticulocyte Lysate System ◽  
Ribonuclease Protection ◽  
Carboxy Terminal

Rat ventricular cardiac muscle has previously been shown to contain exceptionally high levels of preproenkephalin mRNA (ppEnk mRNA). We have recently determined that the level of ppEnk mRNA is developmentally and hormonally regulated in rat ventricular cardiac muscle tissue and in cultured myocytes (J. P. Springhorn and W. C. Claycomb. Biochem. J. 258: 73-77, 1989). We demonstrate in the current study that heart ppEnk mRNA is structurally identical at the 5' end to brain ppEnk mRNA using a ribonuclease protection assay and that heart ppEnk mRNA can be translated in vitro using a rabbit reticulocyte lysate system. In vitro synthesized preproenkephalin peptides were immunoprecipitated with a polyclonal antibody directed to the carboxy-terminal seven amino acids of preproenkephalin. We have also established by radioimmunoassay that enkephalin-containing peptides are secreted from cultured neonatal and adult rat ventricular cardiac muscle cells. This secretion is linear with respect to time and can be stimulated by phorbol 12-myristate 13-acetate (PMA) and adenosine 3',5'-cyclic monophosphate (cAMP). It was determined by column chromatography that cAMP induced neonatal rat ventricular cardiac muscle cells to secrete Met5-enkephalin-Arg6-Phe7, whereas PMA plus 3-isobutyl-1-methylxanthine induced adult rat ventricular cardiac muscle cells to secrete Met5-enkephalin. These studies establish that ventricular heart muscle ppEnk mRNA can be translated and that enkephalin peptides are secreted from ventricular cardiac muscle cells.

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