Fatty acids and phospholipids of adult and newborn rat hearts and of cultured, beating neonatal rat myocardial cells

Triacylglycerol lipase activity with a pH optimum of 5 was present in homogenates of myocardial cells from rat heart. Acid lipase activity was inhibited by serum, heparin, and increased ionic strength. Methylamine, a lysosomotropic agent, did not inhibit the basal or isoproterenol-stimulated rate of endogenous lipolysis as measured by glycerol output from control myocytes. Similarly, accelerated rates of glycerol output that are a consequence of an elevation in the intracellular stores of triacylglycerols in myocytes from diabetic rat hearts and from myocytes prepared with free fatty acids in the isolation solutions were not reduced by methylamine. Therefore, the acid lysosomal triacylglycerol lipase must not be involved in the mobilization of endogenous triacylglycerols in myocardial cells from rat heart.

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Lipolysis in isolated myocardial cells from diabetic rat hearts

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1985.249.5.h1024 ◽

1985 ◽

Vol 249 (5) ◽

pp. H1024-H1030 ◽

Cited By ~ 2

Author(s):

K. A. Kenno ◽

D. L. Severson

Keyword(s):

Fatty Acids ◽

Free Fatty Acids ◽

Diabetic Rat ◽

Myocardial Cells ◽

Atp Content ◽

Intracellular Accumulation ◽

Rat Hearts ◽

Triacylglycerol Content ◽

Release Of Glycerol ◽

Stimulation Of

Diabetes in rats was induced with streptozotocin (100 mg/kg); myocardial cells (myocytes) were isolated from the hearts 3-4 days later. Diabetic myocytes were characterized as having the same viability and ATP content as control myocytes, but the yield was reduced. The triacylglycerol content of diabetic myocytes was elevated by 3.7-fold; this resulted in an increased rate of glycerol output during subsequent incubations. There was a stoichiometric relationship between the decline in the cellular triacylglycerol content and the release of glycerol into the incubation medium. Isoproterenol stimulated the output of glycerol from control myocytes by about twofold, but the stimulation of glycerol output from diabetic myocytes by isoproterenol was markedly less. The combination of 1-methyl-3-isobutylxanthine with isoproterenol or 8-(4-chlorophenylthio)-adenosine 3',5'-cyclic monophosphate also failed to produce the same lipolytic response in diabetic myocytes as in control myocytes. Triacylglycerol-loaded myocytes from control rats, prepared by including palmitate in the isolation buffers, were also characterized as having increased basal rates of glycerol output and a reduced lipolytic response to isoproterenol. The level of free fatty acids in diabetic myocytes was 2.8-fold greater than in myocytes from control hearts. The intracellular accumulation of free fatty acids in these quiescent populations of diabetic myocytes may limit the ability of catecholamines to produce a further stimulation of lipolysis.

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Antifibrillating effect of n-3 polyunsaturated fatty acids (PUFA) in aged hypertensive rat hearts

Journal of Molecular and Cellular Cardiology ◽

10.1016/j.yjmcc.2007.03.034 ◽

2007 ◽

Vol 42 (6) ◽

pp. S12

Author(s):

Marcela Fialova ◽

Katarina Dlugosova ◽

Vladimir Knezl ◽

Ludmila Okruhlicova ◽

Jan Drimal ◽

...

Keyword(s):

Fatty Acids ◽

Polyunsaturated Fatty Acids ◽

Hypertensive Rat ◽

Rat Hearts

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Alpha-1 adrenergic stimulation of cardiac gene transcription in cultured neonatal rat myocardial cells: Effects on myosin light chain-2 gene expression

Journal of Molecular and Cellular Cardiology ◽

10.1016/s0022-2828(87)80706-x ◽

1987 ◽

Vol 19 ◽

pp. S27-S27

Author(s):

S HENDERSON ◽

P DUNNMON ◽

H LEE ◽

R REYNOLDS ◽

D YUAN ◽

...

Keyword(s):

Gene Expression ◽

Gene Transcription ◽

Light Chain ◽

Myosin Light Chain ◽

Neonatal Rat ◽

Myocardial Cells ◽

Adrenergic Stimulation ◽

Myosin Light Chain 2 ◽

Cardiac Gene ◽

Stimulation Of

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Regulation of lysophosphatidylcholine-metabolizing enzymes in isolated myocardial cells from rat heart

Canadian Journal of Physiology and Pharmacology ◽

10.1139/y85-156 ◽

1985 ◽

Vol 63 (8) ◽

pp. 944-951 ◽

Cited By ~ 16

Author(s):

David L. Severson ◽

Thea Fletcher

Keyword(s):

Fatty Acids ◽

Palmitic Acid ◽

Free Fatty Acids ◽

Rat Heart ◽

Marked Reduction ◽

Myocardial Cells ◽

Acyltransferase Activity ◽

Metabolizing Enzymes ◽

Enzymatic Pathways ◽

Lysophospholipase Activity

Enzymatic pathways involved in the metabolism of lysophosphatidylcholine were investigated in rat heart myocardial cells. Acyl CoA-dependent acyltransferase activity was localized in microsomes, and was much greater than lysophospholipase activity in either cytosolic or microsomal fractions. The cytosolic lysophospholipase was more sensitive to inhibition by palmitylcarnitine in comparison to free fatty acids. In contrast, free fatty acids (oleate and palmitate) produced a greater inhibition of the microsomal acyltransferase and lysophospholipase than did palmitylcarnitine. A reduction in the assay pH to 6.5 resulted in an increase in microsomal acyltransferase and cytosolic lysophospholipase activities, but brought about a marked reduction in the microsomal lysophospholipase activity. At pH 6.5, the percentage inhibition of the microsomal acyltransferase by palmitylcarnitine was reduced, whereas the inhibition by palmitic acid was enhanced. The inhibition of the microsomal lysophospholipase by both palmitylcarnitine and palmitic acid was reduced at pH 6.5. With respect to myocardial ischemia, the inhibition of microsomal acyltransferase by free fatty acids and the reduction in microsomal lysophospholipase activity due to acidosis may contribute to the elevation of cellular lysophosphoglycerides which are arrhythmogenic.

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Studies on the action of nystatin on cultured rat myocardial cells and cell membranes, isolated rat hearts, and intact rats

Biochemical Pharmacology ◽

10.1016/0006-2952(84)90040-6 ◽

1984 ◽

Vol 33 (23) ◽

pp. 3779-3786 ◽

Cited By ~ 4

Author(s):

Adorjan Aszalos ◽

June A. Bradlaw ◽

Edilberto F. Reynaldo ◽

George C. Yang ◽

Antoine N. El-Hage

Keyword(s):

Cell Membranes ◽

Myocardial Cells ◽

Rat Hearts ◽

Isolated Rat ◽

Intact Rats

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Abstract P279: YAP, a Transcriptional Cofactor of the Hippo Pathway, Regulates Cardiomyocyte Growth, Survival, and Proliferation

Circulation Research ◽

10.1161/res.109.suppl_1.ap279 ◽

2011 ◽

Vol 109 (suppl_1) ◽

Author(s):

Yanfei Yang ◽

Noritsugu Nakano ◽

Junichi Sadoshima

Keyword(s):

Cardiac Hypertrophy ◽

Hippo Pathway ◽

Neonatal Rat ◽

Border Zone ◽

Luciferase Reporter ◽

Tunel Staining ◽

H2o2 Treatment ◽

Rat Hearts ◽

The Hippo Pathway

Mst1 and Lats2, components of the mammalian Hippo pathway, stimulate apoptosis and inhibit hypertrophy of cardiomyocytes (CMs), thereby mediating reperfusion injury and heart failure. YAP, a transcription factor co-factor, is negatively regulated by the Hippo pathway, and controls cell survival, proliferation and tissue regeneration. The role of YAP in regulating growth and death of CMs is poorly understood. YAP overexpression in CMs induced cardiac hypertrophy, as indicated by increases in cell size (+1.2 fold, p<0.01), protein content (+1.1 fold, p<0.01) and ANF (luciferase reporter activity +1.7 fold, mRNA +2.2 fold, and staining +2.7 fold, p<0.01). Lats2 phosphorylates YAP at Serine 127, which induces cytoplasmic translocation of YAP, whereas YAP(S127A) is localized constitutively in the nucleus. Expression of YAP(S127A) enhanced hypertrophy in cultured CMs compared to that of wild type YAP (+1.87 fold ANF staining, p<0.05), suggesting that the Mst1/Hippo pathway negatively regulates cardiac hypertrophy through YAP. YAP inhibited cell death induced by H2O2 treatment, as evaluated with TUNEL staining (-65%, p<0.05) and CellTiter Blue assays (+34.9%, p<0.01), indicating that YAP plays an essential role in mediating CM survival. Interestingly, YAP also significantly increased Ki67 positive cells in cultured CMs compared to LacZ (+2.65 fold, p<0.05). We used a mouse model of chronic myocardial infarction (MI) to evaluate the function of YAP in the heart in vivo. Although YAP is diffusely localized both in the nucleus and cytosol in CMs in control hearts, CMs in the border zone of MI exhibited nuclear localization of YAP whereas YAP was excluded from the nucleus in CMs in the remodeling area four days after MI (+6.52 fold and +1.28 fold). Some of the YAP positive CMs in the border zone exhibited positive co-staining with Ki67, suggesting that YAP potentially induces CM proliferation. A significant increase in nuclear YAP and Ki67 positive CMs (+2.95 fold, p<0.01 and +2.18 fold, p<0.05) was also observed in neonatal rat hearts whose apex was surgically resected three days before euthanasia. These results suggest that YAP plays an important role in mediating not only hypertrophy and survival, but also proliferation of CMs in response to myocardial injury.

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Different ATP-catabolism in reperfused adult and newborn rat hearts

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1988.254.6.h1091 ◽

1988 ◽

Vol 254 (6) ◽

pp. H1091-H1098

Author(s):

P. W. Achterberg ◽

A. S. Nieukoop ◽

B. Schoutsen ◽

J. W. de Jong

Keyword(s):

Oxidase Activity ◽

Age Groups ◽

Similar Degree ◽

Ischemia And Reperfusion ◽

Xanthine Oxidoreductase ◽

Newborn Rat ◽

Age Related ◽

Rat Hearts ◽

Age Dependent ◽

Atp Breakdown

Age-dependent differences in the effects of ischemia and reperfusion on ATP breakdown were studied in perfused adult and newborn (10 days old) rat hearts. No-flow ischemia (15 min at 37, 30, or 23 degrees C) was applied and reperfusion (20 min at 37 degrees C) was studied after ischemia at 23 or 37 degrees C. Hypothermia during ischemia protected both age groups to a similar degree against ATP decline, which was linear with temperature. Reperfusion after normothermic ischemia resulted in higher ATP levels in newborn hearts with less release of ATP catabolites (purines). We found no age-related differences in lactate release but large differences in purine release. During normoxia, adult hearts released mainly urate (80% of total) and inosine (7%), but newborns released hypoxanthine (64%) and inosine (15%). Early during reperfusion adult hearts released inosine (58%) and adenosine (18%), but newborns released inosine (53%) and hypoxanthine (38%). These data suggested a lower activity of the potentially deleterious enzyme xanthine oxidoreductase in newborn hearts, which was confirmed by enzymatic assay. ATP-catabolite release during reperfusion was less in newborn than adult hearts, and this coincided with lower xanthine oxidase activity.

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