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.

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.

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.

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 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

Contraction-induced injury to single muscle fibers: velocity of stretch does not influence the force deficit

1998 ◽  
Vol 275 (6) ◽  
pp. C1548-C1554 ◽  
Author(s):  
Gordon S. Lynch ◽  
John A. Faulkner
Keyword(s):  
Null Hypothesis ◽  
Muscle Injury ◽  
Isometric Force ◽  
Muscle Fibers ◽  
Single Muscle ◽  
Control Value ◽  
Severity Of Injury ◽  
Before And After ◽  
The Difference ◽  
Permeabilized Fibers

We tested the null hypothesis that the severity of injury to single muscle fibers following a single pliometric (lengthening) contraction is not dependent on the velocity of stretch. Each single permeabilized fiber obtained from extensor digitorum longus muscles of rats was maximally activated and then exposed to a single stretch of either 5, 10, or 20% strain [% of fiber length ( L f)] at a velocity of 0.5, 1.0, or 2.0 L f /s. The force deficit, the difference between maximum tetanic isometric force (Po) before and after the stretch expressed as a percentage of the control value for Po before the stretch, provided an estimate of the magnitude of muscle injury. Despite a fourfold range from the lowest to the highest velocities, force deficits were not different among stretches of the same strain. At stretches of 20% strain, even an eightfold range of velocities produced no difference in the force deficit, although 40% of the fibers were torn apart at a velocity of 4 L f /s. We conclude that, within the range of velocities tolerated by single permeabilized fibers, the severity of contraction-induced injury is not related to the velocity of stretch.

MHC and sarcoplasmic reticulum protein isoforms in functionally overloaded cat plantaris muscle fibers

1996 ◽  
Vol 80 (4) ◽  
pp. 1296-1303 ◽  
Author(s):  
R. J. Talmadge ◽  
R. R. Roy ◽  
G. R. Chalmers ◽  
V. R. Edgerton
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Heavy Chain ◽  
Muscle Fibers ◽  
Protein Isoforms ◽  
Type I ◽  
Single Muscle ◽  
Plantaris Muscle ◽  
Plasmic Reticulum ◽  
Deep Region ◽  
Isoform Expression

To determine whether the adaptations in myosin heavy chain (MHC) isoform expression after functional overload (FO) are accompanied by commensurate adaptations in protein isoforms responsible for relaxation [sarco(endo)plasmic reticulum (SR) Ca(2+)-adenosinetriphosphatase (SERCA) and phospholamban (PHL)] in single muscle fibers, the isoforms of MHC and SERCA and the presence or absence of PHL were determined for cat plantaris fibers 3 mo after FO. In control plantaris the relative MHC isoform composition was 23% type I, 21% type IIa, and 56% type IIb. FO resulted in a shift toward slower isoforms (33% type I, 44% type IIa, and 23% type IIb). In the deep region of the plantaris the proportions of type I MHC and hybrid MHC fibers (containing type I and II MHCs) were 40 and 200% greater in FO cats, respectively. FO resulted in a 47% increase in the proportion of fibers containing only the slow SERCA isoform (SERCA2) and a 41% increase in the proportion of fibers containing PHL. The proportions of fibers containing type I MHC, SERCA2, and PHL in control and FO plantaris were linearly correlated. These data show that adaptations in MHC isoform expression are accompanied by commensurate adaptations in sarcoplasmic reticulum protein isoforms in single muscle fibers after FO.

Sign in / Sign up

Export Citation Format

Share Document