scholarly journals Arsenazo III and antipyrylazo III calcium transients in single skeletal muscle fibers.

1982 ◽  
Vol 79 (4) ◽  
pp. 679-707 ◽  
Author(s):  
P Palade ◽  
J Vergara
Keyword(s):  
Skeletal Muscle ◽  
Voltage Clamp ◽  
Spectral Characteristics ◽  
Muscle Fibers ◽  
Calcium Transients ◽  
Arsenazo Iii ◽  
Tension Development ◽  
Skeletal Muscle Fibers ◽  
Concentration Changes

The metallochrome calcium indicators arsenazo III and antipyrylazo III have been introduced individually into cut single frog skeletal muscle fibers from which calcium transients have been elicited either by action potential stimulation or by voltage-clamp pulses of up to 50 ms in duration. Calcium transients recorded with both dyes at selected wavelengths have similar characteristics when elicited by action potentials. Longer voltage-clamp pulse stimulation reveals differences in the late phases of the optical signals obtained with the two dyes. The effects of different tension blocking methods on Ca transients were compared experimentally. Internal application of EGTA at concentrations up to 3 mM was demonstrated to be efficient in blocking movement artifacts without affecting Ca transients. Higher EGTA concentrations affect the Ca signals' characteristics. Differential effects of internally applied EGTA on tension development as opposed to calcium transients suggest that diffusion with binding from Ca++ release sites to filament overlap sites may be significant. The spectral characteristics of the absorbance transients recorded with arsenazo III suggest that in situ recorded signals cannot be easily interpreted in terms of Ca concentration changes. A more exhaustic knowledge of the dye chemistry and/or in situ complications in the use of the dye will be necessary.

scholarly journals Role of Nebulin on Actomyosin Interaction Studied in situ in Demembranated Skeletal Muscle Fibers from Newborn Mice

2009 ◽  
Vol 96 (3) ◽  
pp. 127a
Author(s):  
M.L. Bang ◽  
M. Caremani ◽  
E. Brunello ◽  
R. Littlefield ◽  
R. Lieber ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Fibers ◽  
Newborn Mice ◽  
Skeletal Muscle Fibers ◽  
Actomyosin Interaction

scholarly journals Optical signals from surface and T system membranes in skeletal muscle fibers. Experiments with the potentiometric dye NK2367.

1982 ◽  
Vol 80 (2) ◽  
pp. 203-230 ◽  
Author(s):  
J A Heiny ◽  
J Vergara
Keyword(s):  
Skeletal Muscle ◽  
Voltage Clamp ◽  
Surface Membrane ◽  
Muscle Fibers ◽  
Optical Signal ◽  
Intensity Change ◽  
Optical Signals ◽  
Potential Control ◽  
Skeletal Muscle Fibers ◽  
T System

Absorbance signals were recorded from cut single skeletal muscle fibers stained with the nonpenetrating potentiometric dye NK2367 and mounted in a three-vaseline-gap voltage clamp. The characteristics of the optical signals recorded under current and voltage-clamp conditions were studied at various wavelengths between 500 and 800 nm using unpolarized light. Our results indicate that the absorbance signals recorded with this dye reflect potential changes across both the surface and T system membranes and that the relative contribution of each of these membrane compartments to the total optical change is strongly wavelength dependent. A peak intensity change was detected at 720 nm for the surface membrane signal and at 670 nm for the T system. Evidence for this wavelength-dependent separation derives from an analysis of the kinetics and voltage dependence of the optical signals at different wavelengths, and results obtained in detubulated fibers. The 670-nm optical signal was used to demonstrate the lack of potential control in the T system by the voltage clamp and the effect of a tetrodotoxin (TTX)-sensitive sodium conductance on tubular depolarization.

scholarly journals Calcium-gated calcium channels in sarcoplasmic reticulum of rabbit skinned skeletal muscle fibers.

1986 ◽  
Vol 87 (2) ◽  
pp. 289-303 ◽  
Author(s):  
P Volpe ◽  
G Salviati ◽  
A Chu
Keyword(s):  
Skeletal Muscle ◽  
Sarcoplasmic Reticulum ◽  
Isometric Force ◽  
Muscle Fibers ◽  
Ruthenium Red ◽  
Scattering Method ◽  
Tension Development ◽  
Maximal Force ◽  
Skeletal Muscle Fibers ◽  
Ca2 Channels

The action of ruthenium red (RR) on Ca2+ loading by and Ca2+ release from the sarcoplasmic reticulum (SR) of chemically skinned skeletal muscle fibers of the rabbit was investigated. Ca2+ loading, in the presence of the precipitating anion pyrophosphate, was monitored by a light-scattering method. Ca2+ release was indirectly measured by following tension development evoked by caffeine. Stimulation of the Ca2+ loading rate by 5 microM RR was dependent on free Ca2+, being maximal at pCa 5.56. Isometric force development induced by 5 mM caffeine was reversibly antagonized by RR. IC50 for the rate of tension rise was 0.5 microM; that for the extent of tension was 4 microM. RR slightly shifted the steady state isometric force/pCa curve toward lower pCa values. At 5 microM RR, the pCa required for half-maximal force was 0.2 log units lower than that of the control, and maximal force was depressed by approximately 16%. These results suggest that RR inhibited Ca2+ release from the SR and stimulated Ca2+ loading into the SR by closing Ca2+-gated Ca2+ channels. Previous studies on isolated SR have indicated the selective presence of such channels in junctional terminal cisternae.

Calcium Signaling in Isolated Skeletal Muscle Fibers Investigated Under "Silicone Voltage-Clamp" Conditions

2004 ◽  
Vol 40 (2) ◽  
pp. 225-236 ◽  
Author(s):  
Claude Collet ◽  
Sandrine Pouvreau ◽  
Laszlo Csernoch ◽  
Bruno Allard ◽  
Vincent Jacquemond
Keyword(s):  
Skeletal Muscle ◽  
Calcium Signaling ◽  
Voltage Clamp ◽  
Muscle Fibers ◽  
Skeletal Muscle Fibers

scholarly journals An improved vaseline gap voltage clamp for skeletal muscle fibers.

1976 ◽  
Vol 67 (3) ◽  
pp. 265-293 ◽  
Author(s):  
B Hille ◽  
D T Campbell
Keyword(s):  
Skeletal Muscle ◽  
Voltage Clamp ◽  
Sodium Current ◽  
Muscle Fibers ◽  
Complex Impedance ◽  
Sodium Currents ◽  
Disk Model ◽  
Transverse Tubular System ◽  
Skeletal Muscle Fibers ◽  
Tubular System

A Vaseline gap potentiometric recording and voltage clamp method is developed for frog skeletal muscle fibers. The method is based on the Frankenhaeuser-Dodge voltage clamp for myelinated nerve with modifications to improve the frequency response, to compensate for external series resistance, and to compensate for the complex impedance of the current-passing pathway. Fragments of single muscle fibers are plucked from the semitendinosus muscle and mounted while depolarized by a solution like CsF. After Vaseline seals are formed between fluid pools, the fiber ends are cut once again, the central region is rinsed with Ringer solution, and the feedback amplifiers are turned on. Errors in the potential and current records are assessed by direct measurements with microelectrodes. The passive properties of the preparation are simulated by the "disk" equivalent circuit for the transverse tubular system and the derived parameters are similar to previous measurements with microelectrodes. Action potentials at 5 degrees C are long because of the absence of delayed rectification. Their shape is approximately simulated by solving the disk model with sodium permeability in the surface and tubular membranes. Voltage clamp currents consist primarily of capacity currents and sodium currents. The peak inward sodium current density at 5 degrees C is 3.7 mA/cm2. At 5 degrees C the sodium currents are smoothly graded with increasing depolarization and free of notches suggesting good control of the surface membrane. At higher temperatures a small, late extra inward current appears for small depolarizations that has the properties expected for excitation in the transverse tubular system. Comparison of recorded currents with simulations shows that while the transverse tubular system has regenerative sodium currents, they are too small to make important errors in the total current recorded at the surface under voltage clamp at low temperature. The tubules are definitely not under voltage clamp control.

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