scholarly journals Excitation-contraction coupling: role of K-activation within the transverse tubular system.

1983 ◽  
Vol 80 (4) ◽  
pp. 988-992
Author(s):  
J. P. Reuben ◽  
G. M. Katz ◽  
P. W. Brandt ◽  
G. Suarez-Kurtz ◽  
M. S. Dekin
Keyword(s):  
Excitation Contraction Coupling ◽  
Transverse Tubular System ◽  
Contraction Coupling ◽  
Tubular System

scholarly journals Evidence for Anion-Permselective Membrane in Crayfish Muscle Fibers and Its Possible Role in Excitation-Contraction Coupling

1963 ◽  
Vol 47 (1) ◽  
pp. 189-214 ◽  
Author(s):  
Lucien Girardier ◽  
John P. Reuben ◽  
Philip W. Brandt ◽  
Harry Grundfest
Keyword(s):  
Muscle Fibers ◽  
Current Loop ◽  
Excitation Contraction Coupling ◽  
Transverse Tubular System ◽  
Contraction Coupling ◽  
Permselective Membrane ◽  
Tubular System ◽  
Inward Currents ◽  
A Current ◽  
T System

Under certain conditions only, isolated crayfish skeletal muscle fibers change in appearance, becoming grainy, darkening, and seemingly losing their striations. These changes result from development of large vesicles on both sides of the Z-line. The longitudinal sarcoplasmic reticulum remains unaffected. The vesicles are due to swelling of a transverse tubular system (TTS) which is presumably homologous with the T-system tubules of other muscle fibers. The vesiculations occur during efflux of water or on reducing external K or Cl, but only when KCl can leave the fiber. They never result from osmotic, ionic, or electrical changes when KCl cannot leave. Inward currents, applied through a KCl-filled intracellular cathode, also cause the vesiculations. These are not produced when the cathode is filled with K-propionate, nor by outward or longitudinal currents. Thus the transverse tubules swell only when Cl leaves the cell. Accordingly, their membrane is largely or exclusively anion-permselective. These findings also indicate that the TTS forms part of a current loop, connecting with the exterior of the fiber probably through radial tubules (RT) possessing membrane of low conductivity. Thus, part of the current flowing inward across the sarcolemma during activity can return to the exterior through the membrane of the TTS. The structure and properties of the latter offer the possibility for an efficient electrical mechanism to initiate excitation-contraction coupling.

scholarly journals Action Potentials, Afterpotentials, and Excitation-Contraction Coupling in Frog Sartorius Fibers without Transverse Tubules

1969 ◽  
Vol 53 (3) ◽  
pp. 298-310 ◽  
Author(s):  
Peter W. Gage ◽  
Robert S. Eisenberg
Keyword(s):  
Membrane Potential ◽  
Short Duration ◽  
Action Potentials ◽  
Sartorius Muscle ◽  
Transverse Tubules ◽  
Excitation Contraction Coupling ◽  
Transverse Tubular System ◽  
Contraction Coupling ◽  
Tubular System ◽  
Frog Sartorius

In frog sartorius muscle fibers in which the transverse tubular system has been disrupted by treatment with glycerol, action potentials which are unaccompanied by twitches can be recorded. These action potentials appear to be the same as those recorded in normal fibers except that the early afterpotential usually consists of a small hyperpolarization of short duration. After a train of action potentials no late afterpotential is seen even when the membrane potential is changed from the resting level. In fibers without transverse tubules hyperpolarizing currents do not produce a creep in potential. The interruption of excitation-contraction coupling, the changes in the afterpotentials, and the disappearance of creep are all attributed to the lack of a transverse tubular system.

scholarly journals Remodeling of t-system and proteins underlying excitation-contraction coupling in aging versus failing human heart

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Yankun Lyu ◽  
Vipin K. Verma ◽  
Younjee Lee ◽  
Iosif Taleb ◽  
Rachit Badolia ◽  
...  
Keyword(s):  
Heart Function ◽  
Ventricular Myocardium ◽  
Left Ventricular ◽  
Left Ventricular Myocardium ◽  
Excitation Contraction Coupling ◽  
Transverse Tubular System ◽  
Contraction Coupling ◽  
Senescent Phenotype ◽  
Cellular Microstructure ◽  
T System

AbstractIt is well established that the aging heart progressively remodels towards a senescent phenotype, but alterations of cellular microstructure and their differences to chronic heart failure (HF) associated remodeling remain ill-defined. Here, we show that the transverse tubular system (t-system) and proteins underlying excitation-contraction coupling in cardiomyocytes are characteristically remodeled with age. We shed light on mechanisms of this remodeling and identified similarities and differences to chronic HF. Using left ventricular myocardium from donors and HF patients with ages between 19 and 75 years, we established a library of 3D reconstructions of the t-system as well as ryanodine receptor (RyR) and junctophilin 2 (JPH2) clusters. Aging was characterized by t-system alterations and sarcolemmal dissociation of RyR clusters. This remodeling was less pronounced than in HF and accompanied by major alterations of JPH2 arrangement. Our study indicates that targeting sarcolemmal association of JPH2 might ameliorate age-associated deficiencies of heart function.

Extracellular divalent cations in excitation–contraction coupling: hypertonic solution effects

1982 ◽  
Vol 60 (4) ◽  
pp. 440-445
Author(s):  
Isao Oota ◽  
Isao Kosaka ◽  
Torao Nagai ◽  
Hideyo Yabu
Keyword(s):  
Skeletal Muscle ◽  
Divalent Cations ◽  
Muscle Fibers ◽  
Hypertonic Solution ◽  
Excitation Contraction Coupling ◽  
Contraction Coupling ◽  
Skeletal Muscle Fibers ◽  
Membrane Bound

It is the purpose of this article to point out that the membrane-bound Ca plays an important role in excitation–contraction (E–C) coupling of skeletal muscle fibers and that other divalent cations are unable to substitute for this role of membrane-bound Ca.

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