Dependence of the contractile activation of skinned cardiac cells on the sarcomere length

Nature ◽  
1975 ◽  
Vol 256 (5512) ◽  
pp. 54-56 ◽  
Author(s):  
ALEXANDRE FABIATO ◽  
FRANÇOISE FABIATO
Keyword(s):  
Sarcomere Length ◽  
Cardiac Cells ◽  
Contractile Activation

scholarly journals Sarcomere length-resting tension relation in single frog atrial cardiac cells.

1979 ◽  
Vol 45 (4) ◽  
pp. 554-559 ◽  
Author(s):  
M Tarr ◽  
J W Trank ◽  
P Leiffer ◽  
N Shepherd
Keyword(s):  
Sarcomere Length ◽  
Cardiac Cells ◽  
Resting Tension

Skeletal and Cardiac Muscle Contractile Activation: Tropomyosin “Rocks and Rolls”

Physiology ◽  
2001 ◽  
Vol 16 (2) ◽  
pp. 49-55 ◽  
Author(s):  
A. M. Gordon ◽  
M. Regnier ◽  
E. Homsher
Keyword(s):  
Cardiac Muscle ◽  
Thin Filament ◽  
Sarcomere Length ◽  
Force Development ◽  
Cross Bridge ◽  
Functional Differences ◽  
Filament Structure ◽  
Muscle Types ◽  
Contractile Activation ◽  
Muscle Contractile

Changes in thin filament structure induced by Ca2+ binding to troponin and subsequent strong cross-bridge binding regulate additional strong cross-bridge attachment, force development, and dependence of force on sarcomere length in skeletal and cardiac muscle. Variations in activation properties account for functional differences between these muscle types.

scholarly journals Myofilament-generated tension oscillations during partial calcium activation and activation dependence of the sarcomere length-tension relation of skinned cardiac cells.

1978 ◽  
Vol 72 (5) ◽  
pp. 667-699 ◽  
Author(s):  
A Fabiato ◽  
F Fabiato
Keyword(s):  
Sarcomere Length ◽  
Rapid Decrease ◽  
Cardiac Cells ◽  
Maximal Velocity ◽  
Active Tension ◽  
Velocity Of Shortening ◽  
Rigor Tension ◽  
The Mean ◽  
Rat Ventricle ◽  
Full Activation

During partial Ca2+ activation, skinned cardiac cells with sarcoplasmic reticulum destroyed by detergent developed spontaneous tension oscillations consisting of cycles (0.1-1 Hz) of rapid decrease of tension corresponding to the yield of some sarcomeres and slow redevelopment of tension corresponding to the reshortening of these sarcomeres. Such myofilament-generated tension oscillations were never observed during the full activation induced by a saturating [free Ca2+] or during the rigor tension induced by decreasing [MgATP] in the absence of free Ca2+ or when the mean sarcomere length (SL) of the preparation was greater than 3.10 microm during partial Ca2+ activation. A stiff parallel elastic element borne by a structure that could be digested by elastase hindered the study of the SL--active tension diagram in 8-13-microm-wide skinned cells from the rat ventricle, but this study was possible in 2-7-microm-wide myofibril bundles from the frog or dog ventricle. During rigor the tension decreased linearly when SL was increased from 2.35 to 3.80 microm. During full Ca2+ activation the tension decreased by less than 20% when SL was increased from 2.35 to approximately 3.10 microm. During partial Ca2+ activation the tension increased when SL was increased from 2.35 to 3.00 microm. From this observation of an apparent increase in the sensitivity of the myofilaments to Ca2+ induced by increasing SL during partial Ca2+ activation, a model was proposed that describes the tension oscillations and permits the derivation of the maximal velocity of shortening (Vmax). Vmax was increased by increasing [free Ca2+] or decreasing [free Mg2+] but not by increasing SL.

Direct measurement of sarcomere length from isolated cardiac cells

1982 ◽  
Vol 242 (1) ◽  
pp. H68-H78 ◽  
Author(s):  
K. P. Roos ◽  
A. J. Brady ◽  
S. T. Tan
Keyword(s):  
Data Storage ◽  
Sarcomere Length ◽  
Cardiac Cells ◽  
Isolated Cells ◽  
Cardiac Muscle Cells ◽  
Charge Coupled Device ◽  
Hypertonic Stress ◽  
Intact Membrane ◽  
Photodiode Array ◽  
Isolated Cardiac Cells

Isolated cardiac muscle cells enzymatically digested with collagenase and hyaluronidase from whole rat myocardium demonstrate the characteristics of an intact membrane in that they tolerate millimolar concentrations of free Ca2+ and exhibit phasic contractions with electrical excitation. These isolated cells maintain their characteristic A-I band striation patterns when at rest or during contraction. An apparatus has been developed to directly image these cells with phase-contrast micrography onto a 1,728-element charge-coupled device photodiode array for rapid data storage in a digital computer. The digitized striation pattern profile was analyzed for individual and average sarcomere spacing. In isotonic media the average resting sarcomere length ranged from 1.77 to 1.91 micrometers in 13 cells, with a mean length of 1.83 +/- 0.12 micrometers. Electrically stimulated phasic contractions in three cells demonstrated a synchronous 20% decrease in sarcomere spacing to a mean of 1.51 micrometers. Striation spacing decreased under hypertonic stress but elongated only up to 1.93 micrometers in hypotonic solutions, suggesting that some internal elastic constraint exists that limits elongation of the cell.

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