Cytosolic calcium and myofilaments in single rat cardiac myocytes achieve a dynamic equilibrium during twitch relaxation.

@article{Spurgeon1992CytosolicCA,
  title={Cytosolic calcium and myofilaments in single rat cardiac myocytes achieve a dynamic equilibrium during twitch relaxation.},
  author={Harold A. Spurgeon and William H. duBell and Michael D. Stern and Steven J. Sollott and Bruce D. Ziman and Howard S. Silverman and Maurizio Colognesi Capogrossi and A Talo and Edward G. Lakatta},
  journal={The Journal of Physiology},
  year={1992},
  volume={447}
}
1. Single isolated rat cardiac myocytes were loaded with either the pentapotassium salt form or the acetoxymethyl ester (AM) form of the calcium‐sensitive fluorescent probe, Indo‐1. The relationship of the Indo‐1 fluorescence transient, an index of the change in cytosolic calcium [Ca2+]i concentration, to the simultaneously measured cell length during the electrically stimulated twitch originating from slack length at 23 degrees C was evaluated. It was demonstrated that even if the Ca2… Expand
Estimation of myofibrillar responsiveness to Ca2+ in isolated rat ventricular myocytes
TLDR
It is concluded that the R-L trajectory is useful for estimating the myofibrillar responsiveness to Ca2+ in isolated myocytes and may be beneficial for the evaluation of inotropic agents. Expand
Myofilament Ca 2+ sensitivity in ventricular myocytes from streptozotocin-induced diabetic rat
Contractile dysfunction is a frequently reported complication of diabetic cardiomyopathy and many of the defects observed in the clinical setting have also been reported in experimentally-inducedExpand
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Whether and to what extent the trans‐sarcolemmal Ca2+ influx is immediately sequestered by the sarcoplasmic reticulum (SR) is investigated to determine. Expand
The relationship between contractile force and intracellular [Ca2+] in intact rat cardiac trabeculae
TLDR
It is concluded that the relationship of force to [Ca2+]i during physiological twitch contractions cannot be used to predict the steady state relationship. Expand
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TLDR
The results suggest that the R-L trajectory is a useful method to estimate the myofibrillar responsiveness to Ca(2+) in isolated mouse myocytes and can be applied to various mouse models of heart disease. Expand
Regulation of unloaded cell shortening by sarcolemmal sodium‐calcium exchange in isolated rat ventricular myocytes.
1. Regulation of unloaded cell shortening and relaxation by sarcolemmal Na(+)‐Ca2+ exchange was investigated in rat ventricular myocytes. Contraction of single cells at 22 +/‐ 1 degrees C wasExpand
Role of Ca2+ availability to myofilaments and their sensitivity to Ca2+ in myocyte contractile dysfunction in heart failure.
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Using both intact and skinned cellular preparations, a potential defect in myocyte contractile function in HF was a reduction in Ca2+ availability to the myofilaments, rather than the inherent defects in my ofilament sensitivity to Ca2+. Expand
Rate‐dependent changes of twitch force duration in rat cardiac trabeculae: a property of the contractile system
TLDR
The results suggest that rate‐dependent changes in force and [Ca2+]i transients do not depend on PKA or CaM/kinase II activity but might result from intrinsic features of the contractile and/or Ca2+‐handling proteins. Expand
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TLDR
An improved method was developed for measuring sarcomere length (SML) during twitch contractions of single cardiac ventricular myocytes, using a charge-coupled photodiode array self-scanning at a rate of 1.5 ms/element, and a large variation was observed in contraction time course between myocytes. Expand
8-bromo-cGMP reduces the myofilament response to Ca2+ in intact cardiac myocytes.
TLDR
Analysis of the effects of 8-bromo-cGMP on contraction and simultaneous intracellular Ca2+ transients in intact adult rat ventricular myocytes indicates that cGMP may modulate myocardial relaxation and diastolic tone by reducing the relative myofilament response to Ca2+, probably via cG MP-dependent protein kinase. Expand
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References

SHOWING 1-10 OF 50 REFERENCES
The cytosolic calcium transient modulates the action potential of rat ventricular myocytes.
1. The modulation of the action potential by the cytosolic Ca2+ (Cai2+) transient was studied in single isolated rat ventricular myocytes loaded with the acetoxymethyl ester form of theExpand
The effects of muscle length on intracellular calcium transients in mammalian cardiac muscle.
TLDR
The binding constant of troponin for calcium is a function of developed tension and the shape of the tension‐length relation depends on the procedure used to determine it and this change in shape can be attributed to changes in activation. Expand
Ryanodine releases calcium from sarcoplasmic reticulum in calcium‐tolerant rat cardiac myocytes.
1. The hypothesis tested in this study is that ryanodine depletes sarcoplasmic reticulum (s.r.) Ca2+ loading in suspensions of single adult rat cardiac myocytes by effecting Ca2+ release into theExpand
The effects of changes of pH on intracellular calcium transients in mammalian cardiac muscle.
TLDR
The calcium‐sensitive photoprotein aequorin was micro‐injected into cells of rat, ferret, rabbit and cat papillary muscles to study the effects of changes of pHo and the calcium transient associated with each contraction increased monophasically to a new steady state. Expand
Cytosolic calcium staircase in cultured myocardial cells.
TLDR
To elucidate the mechanism of the tension staircase, chick embryonic myocardial cell aggregates were loaded with the fluorescent cytosolic calcium indicator, indo 1 and found a similar staircase in the diastolic [Ca2+]i, which is also reflected by diastsolic cell edge movement. Expand
Intracellular [Ca2+] related to rate of force development in twitch contraction of heart.
  • D. Yue
  • Chemistry, Medicine
  • The American journal of physiology
  • 1987
TLDR
Evidence is found that the correlation between instantaneous dF/dt and [Ca2+]i is not merely fortuitous but indicates a fundamental property of myocardium, which may represent a central clue as to the mechanism of activation in mammalian cardiac muscle. Expand
Simultaneous measurement of Ca2+, contraction, and potential in cardiac myocytes.
A system is described that can simultaneously record cytosolic Ca2+ concentration ([Ca2+]i), cell length, and either membrane potential or current in single cardiac myocytes loaded with theExpand
Dissociation of changes in apparent myofibrillar Ca2+ sensitivity and twitch relaxation induced by adrenergic and cholinergic stimulation in isolated ferret cardiac muscle
TLDR
The effects of ACh and ISN of modulating the apparent myofilament Ca2+ sensitivity in intact muscles, corroborate findings of previous studies in isolated myofibrillar preparations. Expand
Anoxic contractile failure in rat heart myocytes is caused by failure of intracellular calcium release due to alteration of the action potential.
TLDR
It is concluded that anoxic contractile failure in the rat myocyte is due to alteration of the action potential and the distal pathways of excitation-contraction coupling remain essentially intact. Expand
Relaxation of mammalian single cardiac cells after pretreatment with the detergent Brij‐58.
TLDR
It is concluded that relaxation of the cardiac contractile system is determined basically by an activation‐dependent mechanism, which is masked by load dependence in intact muscle preparations with a well developed calcium sequestering membraneous system. Expand
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