scholarly journals Localization and partial characterization of ADP-ribosylation products in hearts from adult and neonatal rats

1990 ◽  
Vol 270 (3) ◽  
pp. 591-597 ◽  
Author(s):  
K J Piron ◽  
K K McMahon
Keyword(s):  
Rat Heart ◽  
Cardiac Development ◽  
Neonatal Rat ◽  
Nuclear Fraction ◽  
Adult Rats ◽  
Adp Ribosylation ◽  
Adult Rat ◽  
Snake Venom Phosphodiesterase ◽  
Rat Hearts ◽  
Neonatal Rat Heart

The subcellular distributions of endogenous ADP-ribosylation products in hearts from 1-day-old neonatal and adult rats were investigated. In adult rat heart a 52 kDa mono-ADP-ribosylation product was identified in the plasma membrane fraction. In contrast, in neonatal rat heart a 130 kDa poly-ADP-ribosylation product was present in the nuclear fraction. The monomeric and polymeric nature of the two ADP-ribosylation products was determined by their sensitivity to thymidine and by analysis of their snake venom phosphodiesterase products. NADP+ enhanced both the mono- and polymeric reactions. The ADP-ribose-protein linkage of the adult 52 kDa product was stable to 1 h of treatment with hydroxylamine (0.5 M) and mercury ions, but was sensitive to alkali and a 12 h treatment with hydroxylamine (1 M). This is suggestive of an arginine linkage. The 130 kDa poly-ADP-ribosylation product from the neonatal rat heart was alkalilabile but stable to both hydroxylamine and HgCl2. This implies the presence of an unusual linkage in the 130 kDa product. The presence of these different ADP-ribosylation products in adult and neonatal rat hearts suggests the possible importance of these proteins and their ADP-ribosylation during cardiac development.

Effect of strontium on the contractile properties of postnatally developing rat heart ventricles

1985 ◽  
Vol 63 (1) ◽  
pp. 9-17 ◽  
Author(s):  
Matti Vornanen
Keyword(s):  
Rat Heart ◽  
Age Groups ◽  
Contractile Properties ◽  
Neonatal Rat ◽  
Calcium Stores ◽  
Adult Rats ◽  
Adult Rat ◽  
Twitch Potentiation ◽  
Developing Rat ◽  
T System

The effects of substitution of calcium (Ca) by an equimolar concentration of strontium (Sr) on isometric contractions of isolated ventricular muscle from postnatally developing rat heart were studied. The duration of contraction and the time-to-peak tension were increased in all age groups although much less in the adult rats than in the neonates. The contractile force was increased in the muscles of rats between 1 and 14 days of age but was depressed in the older animals. The prominent rest-twitch potentiation of neonatal rat heart in Ca− Tyrode was totally eliminated by Sr, whereas a clear rest-twitch potentiation was induced by this cation in the adult rat heart, in which tissue the potentiation is normally absent in Ca− Tyrode. The maximal twitch potentiation by rest in Ca− Tyrode and the positive inotropic effect of Sr substitution grew from birth up to day 9 and from then gradually declined towards the level of adult rat heart by the end of the 3rd postnatal week. The phase of increasing rest-twitch potentiation coincides fairly well with the known development of sarcoplasmic reticulum and the phase of decline with the appearance of the T system of the sarcolemma. It is suggested that the qualitative changes in the contractile properties of developing rat heart during the 3rd postnatal week are due to the more efficient utilization of intracellular calcium stores, owing to the development of the T system.

Changes in expression of a functional Gi protein in cultured rat heart cells

1988 ◽  
Vol 255 (1) ◽  
pp. C51-C59 ◽  
Author(s):  
I. S. Allen ◽  
S. T. Gaa ◽  
T. B. Rogers
Keyword(s):  
Adenylate Cyclase ◽  
Pertussis Toxin ◽  
Rat Heart ◽  
Neonatal Rat ◽  
Heart Cells ◽  
Dependent Manner ◽  
Camp Accumulation ◽  
Ang Ii ◽  
Rat Heart Myocytes ◽  
Neonatal Rat Heart

The muscarinic cholinergic agonist, carbachol, and pertussis toxin were used to examine the functional status of the guanine nucleotide-binding protein that inhibits adenylate cyclase (Gi) in cultured neonatal rat heart myocytes. The isoproterenol stimulation of adenylate cyclase activity in myocyte membranes and adenosine 3',5'-cyclic monophosphate (cAMP) accumulation in intact cells (4 days in culture) were insensitive to carbachol (0.1 mM). However, in cells cultured for 11 days, carbachol (0.1 mM) inhibited isoproterenol-stimulated cAMP accumulation by 30%. Angiotensin II (ANG II) was also found to inhibit isoproterenol-stimulated cAMP accumulation in day 11 cells in a dose-dependent manner. Pertussis toxin treatment reversed the inhibitory effects of both ANG II and carbachol, suggesting a role for Gi in the process. Carbachol binding to membranes from day 4 cells was relatively insensitive to guanine nucleotides when compared with binding to membranes from day 11 or adult cells. Furthermore, pertussis toxin-mediated 32P incorporation into a 39- to 41-kDa substrate in day 11 membranes was increased 3.2-fold over that measured in day 4 membranes. These findings support the view that, although Gi is expressed, it is nonfunctional in 4-day-old cultured neonatal rat heart myocytes and acquisition of functional Gi is dependent on culture conditions. Furthermore, the ANG II receptor can couple to Gi in heart.

Quantification of calcium paradox in neonatal rat hearts

1987 ◽  
Vol 253 (6) ◽  
pp. H1358-H1364
Author(s):  
J. S. Elz ◽  
W. G. Nayler
Keyword(s):  
Direct Relationship ◽  
Neonatal Rat ◽  
Calcium Paradox ◽  
Ultrastructural Changes ◽  
Adult Rats ◽  
Rat Hearts

Many indexes of damage have been used to quantify the calcium (Ca2+) paradox. We report here how different conclusions may be reached concerning the severity of the paradox when different indexes of damage are used. Hearts from 3- to 24-day-old and adult rats were isolated, depleted of Ca2+ for 5 min, and then Ca2+ repleted. Myoglobin loss, Ca2+ gain, and ultrastructural changes were monitored. Our results indicate that with increasing age each of these parameters shows a progression toward the adult state. However, this progression does not proceed at the same rate for each parameter. There was very little release of myoglobin from hearts of rats of less than 11 days old, but the amount released increased with increasing age. There appeared to be a direct relationship between the amount of myoglobin released and the proportion of extremely contracted cells with disrupted sarcolemma. However, hearts from rats of all ages gained Ca2+, suggesting that Ca2+ entry occurs via contracture-dependent and contracture-independent routes. Thus we are able to dissociate Ca2+ gain from the development of contracted cells and myoglobin release at the youngest ages. Different conclusions could therefore be reached as to the severity of the Ca2+ paradox at these youngest ages depending on which indexes of damage are documented.

Chronotropic effect of histamine on cultured neonatal rat heart cells

1979 ◽  
Vol 58 (2) ◽  
pp. 117-123 ◽  
Author(s):  
Klara Csete ◽  
Marie-Claude Auclair ◽  
Paul Lechat
Keyword(s):  
Rat Heart ◽  
Neonatal Rat ◽  
Heart Cells ◽  
Chronotropic Effect ◽  
Neonatal Rat Heart ◽  
Rat Heart Cells

Expression and cellular distribution of heat-shock and nuclear oncogene proteins in rat hearts

1991 ◽  
Vol 261 (5) ◽  
pp. H1443-H1451 ◽  
Author(s):  
L. H. Snoeckx ◽  
F. Contard ◽  
J. L. Samuel ◽  
F. Marotte ◽  
L. Rappaport
Keyword(s):  
Heat Shock ◽  
Cardiac Development ◽  
Pressure Overload ◽  
Adult Rats ◽  
Coronary Smooth Muscle ◽  
Rat Hearts ◽  
Nonmuscle Cells ◽  
Ontogenic Development ◽  
Coronary Endothelium ◽  
Myocardial Muscle

An early, transient accumulation of mRNAs of the protooncogenes c-fos and c-myc and the heat-shock protein HSP70 has been described in hypertrophying rat hearts. It is unclear 1) in which cardiac cell type-these gene activations occur and 2) whether the corresponding proteins are translated. We studied protein expression in rat hearts during ontogenic development and under stress conditions associated with pressure overload with the use of immunofluorescent techniques. During cardiac development no HSP70 could be detected. c-Fos was expressed consistently after birth but only in coronary smooth muscle cells, and c-Myc was found exclusively in adult coronary endothelium and myocardial nonmuscle cells. In adult rats, HSP70 and, to a lesser extent, c-Fos were induced in myocardial muscle and some nonmuscle cells within 3 h following methohexital sodium anesthesia. A similar, more intense immunolabeling of these peptides was observed after thoracotomy and/or aortic stenosis. The coronary c-Fos and c-Myc labeling remained unchanged in these conditions. Thus the expression in cardiac muscle and nonmuscle cells of the three peptides differs and depends on different triggers.

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