RELEASE OF BOUND SODIUM IN SINGLE MUSCLE FIBERS

1967 ◽  
Vol 45 (4) ◽  
pp. 655-667 ◽  
Author(s):  
J. A. M. Hinke ◽  
S. G. A. McLaughlin
Keyword(s):  
Muscle Fibers ◽  
Ringer Solution ◽  
Bathing Solution ◽  
Single Muscle ◽  
Sodium Ions ◽  
Sodium Potassium ◽  
The Mean

The activities of sodium, potassium, and hydrogen in the myoplasm of single muscle fibers from the giant barnacle were measured by cation-sensitive microelectrodes as the temperature of the bathing solution was increased from 7 to 40 °C. An irreversible shortening occurred in all fibers between 37 and 40 °C. When the fibers shortened in a sodium-free Ringer solution, the mean activity of sodium increased by 130%, the mean activity of potassium remained relatively constant, and the pH decreased from 7.17 to 6.77. The results have been interpreted as meaning that at 37–40 °C there was a disruption of the myofilaments and a release of associated sodium ions.

Na+–Li+ Exchange in Single Muscle Fibers of the Giant Barnacle

1971 ◽  
Vol 49 (10) ◽  
pp. 862-866 ◽  
Author(s):  
R. D. Allen ◽  
J. A. M. Hinke
Keyword(s):  
Muscle Fibers ◽  
Ringer Solution ◽  
Single Muscle ◽  
Slow Exchange ◽  
Rapid Exchange ◽  
One To One ◽  
Two Phases

The net efflux of Na+ was measured in single muscle fibers of the giant barnacle, Balanus nubilus, bathed in Li+-Ringer solution. These experiments indicate one-to-one exchange of Li+ for Na+. This exchange occurs in two phases: a rapid exchange fraction complete within 1 h, and a slow exchange incomplete after 8 h. Intracellular Na+ activity, (aNa)i, decreased more slowly than total fiber Na+ concentration after immersion of the fibers in Li+-Ringer. The implications of this result regarding intracellular Na+ compartmentalization are discussed.

Optical density changes of single muscle fibers in sodium-free solutions

1968 ◽  
Vol 46 (2) ◽  
pp. 247-260 ◽  
Author(s):  
S. G. A. McLaughlin ◽  
J. A. M. Hinke
Keyword(s):  
Optical Density ◽  
Striated Muscle ◽  
Muscle Fibers ◽  
Ringer Solution ◽  
Bathing Solution ◽  
Alkali Metal Cations ◽  
Initial Value ◽  
Striated Muscle Fibers ◽  
Exchange Resins ◽  
Normal Ringer

The optical density, O.D., of single striated muscle fibers from the giant barnacle, Balanus nubilus, was measured at 50-mμ intervals between 450 and 850 mμ. At all wavelengths, the O.D. decreased markedly when the normal Ringer bathing solution was replaced by sodium-free sucrose Ringer solution. For example, at 850 mμ the O.D. of the fibers, relative to the initial value in normal Ringer solution, decreased from 1 to 0.21 ± 0.06 in 25 min. The corresponding increase in the transmittance, T, (O.D. = −log T) was from 5% to 55%. This change in O.D. could be reversed by returning the normal Ringer bathing solution to the bath. Large, reversible decreases in O.D. were also observed when potassium and Tris were used as substitutes for sodium. These changes in O.D. are explained by the theory of light scattering if it is assumed that sodium is bound to macromolecules in the myoplasm. This assumption is supported by experiments with cation-sensitive microelectrodes, which indicate that most of the sodium in the muscle fibers is not free in the myoplasm. When the fibers were bathed in sodium-free, lithium-substituted Ringer solution, a small reversible increase in the O.D. was observed, which may indicate that lithium is complexed more strongly than sodium by macromolecules in the myoplasm. This conclusion is compatible with the known affinities of carboxylate ion exchange resins for the alkali metal cations.

Dichloroacetate accelerates the fall in intracellular Po 2 at onset of contractions inXenopus single muscle fibers

2003 ◽  
Vol 284 (2) ◽  
pp. R481-R485 ◽  
Author(s):  
Richard A. Howlett ◽  
Michael C. Hogan
Keyword(s):  
Steady State ◽  
Time Delay ◽  
Oxidative Metabolism ◽  
Contractile Activity ◽  
Muscle Fibers ◽  
Force Production ◽  
Ringer Solution ◽  
Single Muscle ◽  
Significant Difference ◽  
Significant Step

This study investigated the relationship between intracellular Po 2(Pi O2 ) and dichloroacetate (DCA) administration following a significant step-change increase in oxidative metabolism in intact isolated Xenopus single muscle fibers. Single fibers ( n = 22) were dissected from the lumbrical muscle, injected with the oxygen-sensitive compound palladium- meso-tetra (4-carboxyphenyl) porphine, and randomly assigned to one of two treatment groups. One group (DCA; n = 12) was incubated for 30 min with 1.2 mM DCA, whereas the second group [control (Con); n = 10] was incubated for 30 min in Ringer solution only. After incubation, fibers were electrically stimulated to elicit tetanic contractions (0.5 Hz) for 2 min during which Pi O2 was monitored. Pi O2 before contractions began was 32.0 ± 1.8 and 29.0 ± 1.8 Torr for DCA and Con, respectively, and fell to 6.0 ± 1.3 and 8.8 ± 2.4 Torr (no significant difference), respectively, after steady state was reached. The kinetics of the fall, determined by both the time delay (from the start of contractions to the initial decrease in Pi O2 ) and the tau (63% of the change to a steady state in Pi O2 ), were calculated. In DCA cells, the tau was significantly ( P < 0.05) faster than Con (22.1 ± 3.6 vs. 39.7 ± 5.8 s). In contrast, the time delay was not significantly ( P > 0.45) different between the two groups (11.4 ± 1.7 vs. 12.6 ± 2.3 s, respectively). The amount of fatigue, reflected by a decrease in force production from initial, was not significantly different between groups. These data suggest that by stimulating pyruvate dehydrogenase with DCA in isolated single skeletal muscle cells, the faster fall in Pi O2 is indicative of oxidative metabolism being more rapidly activated. This is the first evidence that oxygen uptake at the onset of contractions may be altered by DCA during moderate- to high-intensity contractile activity.

scholarly journals Peeled mammalian skeletal muscle fibers. Possible stimulation of Ca2+ release via a transverse tubule-sarcoplasmic reticulum mechanism.

1985 ◽  
Vol 86 (4) ◽  
pp. 501-525 ◽  
Author(s):  
S K Donaldson
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Choline Chloride ◽  
Muscle Fibers ◽  
Isometric Tension ◽  
Bathing Solution ◽  
Mammalian Skeletal Muscle ◽  
Single Muscle ◽  
Tension Transient ◽  
Site Of Action ◽  
Stimulation Of

Single muscle fibers from rabbit soleus and adductor magnus and from semitendinosus muscles were peeled to remove the sarcolemma and then stimulated to release Ca2+ by (a) caffeine application or (b) ionic depolarization accomplished via substitution of choline chloride for potassium propionate at constant [K+] X [Cl-] in the bathing solution. Each stimulus, ionic or caffeine, elicited an isometric tension transient that appeared to be due to Ca2+ released from the sarcoplasmic reticulum (SR). The peak magnitude of the ionic (Cl- -induced) tension transient increased with increasing Cl- concentration. The application of ouabain to fibers after peeling had no effect on either type of tension transient. However, soaking the fibers in a ouabain solution before peeling blocked the Cl- -induced but not the caffeine-induced tension transient, which suggests that ouabain's site of action is extracellular, perhaps inside transverse tubules (TTs). Treating the peeled fibers with saponin, which should disrupt TTs to a greater extent than SR membrane, greatly reduced or eliminated the Cl- -induced tension transient without significantly altering the caffeine-induced tension transient. These results suggest that the Cl- -induced tension transient is elicited via stimulation of sealed, polarized TTs rather than via ionic depolarization of the SR.

Contractile inactivation in frog single denervated muscle fibers

1975 ◽  
Vol 229 (6) ◽  
pp. 1492-1497 ◽  
Author(s):  
SC Stuesse ◽  
BD Lindley
Keyword(s):  
Neuromuscular Transmission ◽  
Calcium Concentration ◽  
External Medium ◽  
Fiber Diameter ◽  
Muscle Fibers ◽  
Ringer Solution ◽  
Single Muscle ◽  
Denervated Muscle ◽  
Do Control

After preliminary conditioning depolarizations, single muscle fibers of the frog were tested for ability to contract in response to depolarization by 100 mM K+ Ringer solution. Denervated fibers (6-42 days) lose their ability to produce a 100 mM K+ contracture more rapidly than do control fibers. This decrease in 100 mM K+ contracture size (inactivation) is dependent on length of exposure to and magnitude of the conditioning depolarization and on the calcium concentration in the external medium. At 0.4 mM Ca++, the inactivation is 3 times faster than at 1.5 mM Ca++. The rate of contracture loss is not correlated with fiber diameter or the number of days after failure of neuromuscular transmission, and the preliminary conditioning depolarizations do not affect the rate of terminal relaxation from the 100 mM K+ contractures.

scholarly journals Metabolic evaluation of Crioulo horses participating in competitions of 750 km

2013 ◽  
Vol 33 (12) ◽  
pp. 1471-1477 ◽  
Author(s):  
Lorena Alvariza Amaral ◽  
Millie Marchiori ◽  
Charles Ferreira Martins ◽  
Marcio Nunes Correa ◽  
Carlos Eduardo Wayne Nogueira
Keyword(s):  
Inflammatory Process ◽  
Ionized Calcium ◽  
Metabolic Responses ◽  
Total Calcium ◽  
Blood Cell Count ◽  
Metabolic Evaluation ◽  
Sodium Potassium ◽  
Blood Samples ◽  
Mean Values ◽  
The Mean

The Crioulo breed of horses performs in one of the most physically demanding equestrian competitions, the Marcha de Resistência, which is a contest in which the horses run 750 km in 15 days. The study's aim was to characterize the metabolic responses during this period. We evaluated eleven Crioulo horses in the competition, specifically, two males and nine females. Blood samples were collected 24 hours before the contest and on the 4th, 9th, 11th, 14th and 15th days of competition. We evaluated CK, AST, LDH, glucose, lactate, urea, creatinine, sodium, potassium, chloride, magnesium, total calcium, ionized calcium, total protein, hematocrit and the white blood cell count. At the end of the competition, the mean values of serum AST were 1151±358 IU/ L the mean LDH values were 7418±1695 IU/L and CK was 13,867±3998UI /L. There was a significant increase in urea, creatinine and lactate (p<0.0001). A decrease in the mean values of chloride, sodium, potassium, and total and ionized calcium was observed (p≤0.0002). An evaluation of the total leukocytes and segmented neutrophils (p≤0.0002) revealed their increased values, and decreased values were observed for hematocrit, plasma protein and total lymphocytes (p≤0.0003). The values of glucose, on average, remained constant. Based on these data, we conclude that the Marcha de Resistência competition necessitated a high muscular demand and the depletion of energy and electrolytes, suggesting an inflammatory process in the animals evaluated.

scholarly journals DISSECTION AND ELECTROPHORETIC PROTEIN ANALYSIS OF SINGLE MUSCLE FIBERS FROM HISTOLOGICALLY IDENTIFIED FREEZE-DRIED SECTIONS: APPLICATION TO MUSCLE FIBERS WITH RIMMED VACUOLES

1983 ◽  
Vol 4 (5) ◽  
pp. 459-466 ◽  
Author(s):  
ITARU TOYOSHIMA ◽  
KEIKO TANAKA ◽  
NOBUYOSHI FUKUHARA ◽  
TOSHIHIDE KUMAMOTO ◽  
TADASHI MIYATAKE
Keyword(s):  
Muscle Fibers ◽  
Protein Analysis ◽  
Single Muscle ◽  
Freeze Dried
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