Age-related differences in excitation-contraction coupling in rat papillary muscle

1983 ◽  
Vol 78 (5) ◽  
pp. 492-504 ◽  
Author(s):  
J. M. Capasso ◽  
R. M. Remily ◽  
E. H. Sonnenblick
Keyword(s):  
Papillary Muscle ◽  
Excitation Contraction Coupling ◽  
Contraction Coupling ◽  
Age Related ◽  
Rat Papillary Muscle

Contractile and Ca2+-handling properties of the right ventricular papillary muscle in the late-gestation sheep fetus

2006 ◽  
Vol 101 (3) ◽  
pp. 728-733 ◽  
Author(s):  
T. N. Spencer ◽  
K. J. Botting ◽  
J. L. Morrison ◽  
G. S. Posterino
Keyword(s):  
Right Ventricular ◽  
Papillary Muscle ◽  
Late Gestation ◽  
Postnatal Life ◽  
Excitation Contraction Coupling ◽  
Contraction Coupling ◽  
Force Development ◽  
Uptake Rates ◽  
Significant Difference ◽  
The Right

The force-generating capacity of cardiomyocytes rapidly changes during gestation and early postnatal life coinciding with a transition in cardiomyocyte nucleation in both mice and rats. Changes in nucleation, in turn, appear to coincide with important changes in the excitation-contraction coupling architecture. However, it is not clear whether similar changes are observed in other mammals in which this transition occurs prenatally, such as sheep. Using small (70–300 μM diameter) chemically skinned cardiomyocyte bundles from the right ventricular papillary muscle of sheep fetuses at 126–132 and 137–140 days (d) gestational age (GA), we aimed to examine whether changes in cardiomyocyte nucleation during late gestation coincided with developmental changes in excitation-contraction coupling parameters (e.g., Ca2+ uptake, Ca2+ release, and force development). All experiments were conducted at room temperature (23 ± 1°C). We found that the proportion of mononucleate cardiomyocytes decreased significantly with GA (126–132d, 45.7 ± 4.7%, n = 7; 137–140d, 32.8 ± 1.6%, n = 6; P < 0.05). When we then examined force development between the two groups, there was no significant difference in either the maximal Ca2+-activated force (6.73 ± 1.54 mN/mm2, n = 14 vs. 6.55 ± 1.25 mN/mm2, n = 7, respectively) or the Ca2+ sensitivity of the contractile apparatus (pCa at 50% maximum Ca2+-activated force: 126–132d, 6.17 ± 0.06, n = 14; 137–140d, 6.24 ± 0.08, n = 7). However, sarcoplasmic reticulum (SR) Ca2+ uptake rates (but not Ca2+ release) increased with GA ( P < 0.05). These data reveal that during late gestation in sheep when there is a major transition in cardiomyocyte nucleation, SR Ca2+ uptake rates increase, which would influence total SR Ca2+ content and force production.

scholarly journals Localization of Ca2+ + Mg2+-ATPase of the sarcoplasmic reticulum in adult rat papillary muscle.

1982 ◽  
Vol 93 (3) ◽  
pp. 883-892 ◽  
Author(s):  
A O Jorgensen ◽  
A C Shen ◽  
P Daly ◽  
D H MacLennan
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Cardiac Muscle ◽  
Papillary Muscle ◽  
Functional Role ◽  
Transverse Tubules ◽  
Contraction Coupling ◽  
Adult Rat ◽  
Sarcoplasmic Reticulum Membrane ◽  
Rat Papillary Muscle ◽  
Junctional Sarcoplasmic Reticulum

Localization of the Ca2+ + Mg2+-ATPase of the sarcoplasmic reticulum in rat papillary muscle was determined by indirect immunofluorescence and immunoferritin labeling of cryostat and ultracryotomy sections, respectively. The Ca2+ + Mg2+-ATPase was found to be rather uniformly distributed in the free sarcoplasmic reticulum membrane but to be absent from both peripheral and interior junctional sarcoplasmic reticulum membrane, transverse tubules, sarcolemma, and mitochondria. This suggests that the Ca2+ + Mg2+-ATPase of the sarcoplasmic reticulum is antigenically unrelated to the Ca2+ + Mg2+-ATPase of the sarcolemma. These results are in agreement with the idea that the sites of interior and peripheral coupling between sarcoplasmic reticulum membrane and transverse tubules and between sarcoplasmic reticulum and sarcolemmal membranes play the same functional role in the excitation-contraction coupling in cardiac muscle.

Age-related regulation of excitation–contraction coupling in rat heart

2011 ◽  
Vol 67 (3) ◽  
pp. 317-330 ◽  
Author(s):  
Hilmi B. Kandilci ◽  
Erkan Tuncay ◽  
Esma N. Zeydanli ◽  
Nazli N. Sozmen ◽  
Belma Turan
Keyword(s):  
Rat Heart ◽  
Excitation Contraction Coupling ◽  
Contraction Coupling ◽  
Age Related

scholarly journals CYTOCHEMICAL LOCALIZATION OF CHOLINESTERASE ACTIVITY IN ADULT RABBIT HEART

1971 ◽  
Vol 19 (6) ◽  
pp. 376-381 ◽  
Author(s):  
MARTIN HAGOPIAN ◽  
VIRGINIA M. TENNYSON
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Papillary Muscle ◽  
Cholinesterase Activity ◽  
Acetylcholinesterase Activity ◽  
Rabbit Heart ◽  
Adult Rabbit ◽  
Cytochemical Localization ◽  
Excitation Contraction Coupling ◽  
Contraction Coupling ◽  
T System

The papillary muscle of the adult rabbit heart was studied by a modification of the Koelle-Friedenwald copper thiocholine technique for the localization of cholinesterase activity. Butyrylcholinesterase (BuChE), identified by its substrate and inhibitor specificity, is found mainly in the terminal sacs of the sarcoplasmic reticulum adjacent to the T system. The localization of the reaction product in this particular site suggests that BuChE may play a role in excitation-contraction coupling in the adult rabbit heart. The present findings are also discussed in comparison with our previous work on the localization of acetylcholinesterase activity in the embryonic rabbit heart.

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