Effects of intracellular acidification and varied temperature on force, stiffness, and speed of shortening in frog muscle fibers

2004 ◽  
Vol 287 (1) ◽  
pp. C106-C113 ◽  
Author(s):  
T. Radzyukevich ◽  
K. A. P. Edman
Keyword(s):  
High Temperature ◽  
Rana Temporaria ◽  
Muscle Fibers ◽  
Ringer Solution ◽  
Frog Muscle ◽  
Maximum Force ◽  
Maximum Speed ◽  
Ph Change ◽  
Tibialis Muscle ◽  
Speed Of Shortening

This study aimed to establish whether the temperature-dependent effect of acidification on maximum force observed in mammalian muscles also applies to frog muscle. Measurements of force, stiffness, and unloaded velocity of shortening in intact single muscle fibers from the anterior tibialis muscle of Rana temporaria were performed between 0 and 22°C during fused tetani in H2CO3-CO2-buffered Ringer solution with pH adjusted to 7.0 and 6.3, respectively. The force-to-stiffness ratio increased as a rectilinear function of temperature between 0 and 20°C at pH 7.0. Lowering the pH to 6.3 reduced the tetanic force by 13.5 ± 1.2 and 11.5 ± 1.4% at 2.8 and 20.5°C, respectively, with only a minor reduction in fiber stiffness. The maximum speed of shortening was decreased by lowered pH by 12.9 ± 1.5 and 7.8 ± 1.1% at low and high temperature, respectively. Acidification increased the time to reach 70% of maximum force by 18.0% at ∼2°C; the same pH change performed at ∼20°C in the same fibers reduced the rise time by 24.1%. The same increase in the rate of rise of force at high temperature was also found at normal pH after the fibers were fatigued by frequent stimulation. It is concluded that, in frog muscle, the force-depressant effect of acidification does not vary significantly with temperature. By contrast, acidification affects the onset of activation in a manner that is critically dependent on temperature.

scholarly journals The Mode of Transverse Spread of Contraction Initiated by Local Activation in Single Frog Muscle Fibers

1967 ◽  
Vol 50 (9) ◽  
pp. 2167-2176 ◽  
Author(s):  
Haruo Sugi ◽  
Rikuo Ochi
Keyword(s):  
Muscle Fibers ◽  
Fiber Surface ◽  
Ringer Solution ◽  
Frog Muscle ◽  
Transverse Tubular System ◽  
Local Activation ◽  
Current Pulses ◽  
Negative Current ◽  
Tubular System

Isolated single frog muscle fibers were locally activated by applying negative current pulses to a pipette whose tip was in contact with the fiber surface. In contrast to the graded inward spread of contraction initiated by a moderate depolarization, the contraction in response to a strong negative current was observed to spread transversely around the whole perimeter but not through the center of the fiber. This response was elicited only with pipettes of more than 6 µ diameter. The response was still present if the sodium of the Ringer solution was replaced by choline, or the chloride was replaced by nitrate or propionate. The duration of the response appeared to be independent of the duration of stimulating current in fresh fibers, while the contraction lasted as long as the current went on in deteriorated fibers. The contraction was first initiated at the area of fiber surface covered by the pipette, and spread around the perimeter of the fiber with a velocity of 0.8–6 cm/sec. Possible mechanisms of the response are discussed in connection with the properties of the transverse tubular system, the possibility of some self-propagating process along the walls of the tubules being suggested.

scholarly journals The influence of free calcium on the maximum speed of shortening in skinned frog muscle fibres.

1986 ◽  
Vol 380 (1) ◽  
pp. 257-273 ◽  
Author(s):  
F J Julian ◽  
L C Rome ◽  
D G Stephenson ◽  
S Striz
Keyword(s):  
Frog Muscle ◽  
Maximum Speed ◽  
Free Calcium ◽  
Muscle Fibres ◽  
Speed Of Shortening

scholarly journals The maximum speed of shortening in living and skinned frog muscle fibres.

1986 ◽  
Vol 370 (1) ◽  
pp. 181-199 ◽  
Author(s):  
F J Julian ◽  
L C Rome ◽  
D G Stephenson ◽  
S Striz
Keyword(s):  
Frog Muscle ◽  
Maximum Speed ◽  
Muscle Fibres ◽  
Speed Of Shortening

Maximum shortening speed of motor units of various types in cat lumbrical muscles

1993 ◽  
Vol 69 (2) ◽  
pp. 442-448 ◽  
Author(s):  
J. Petit ◽  
M. Chua ◽  
C. C. Hunt
Keyword(s):  
Motor Unit ◽  
Inverse Correlation ◽  
Motor Units ◽  
Maximum Speed ◽  
Single Motor Units ◽  
Maximal Speed ◽  
Contraction Times ◽  
Isometric Twitch ◽  
Lumbrical Muscles ◽  
Speed Of Shortening

1. Isotonic shortening of cat superficial lumbrical muscles was studied during maximal tetanic contractions of single motor units of identified types. For each motor unit, the maximal speed of contraction, Vmax, was determined by extrapolating to zero the hyperbolic relation between applied tension and speed of shortening. 2. The maximal speeds of shortening of motor units formed a continuum with the highest velocities observed for the fast fatigable motor units and the lowest for the slow motor units. 3. On average, the maximum speed of shortening increased with the tetanic tension developed by the motor units. 4. In motor units with isometric twitch contraction times less than 35 ms, these times showed a significant inverse correlation with Vmax. Progressively longer contraction times were associated with rather small changes in Vmax. 5. The implications of these findings on the speed of muscle shortening during motor-unit recruitment are discussed.

scholarly journals Globular and asymmetric acetylcholinesterase in frog muscle basal lamina sheaths.

1986 ◽  
Vol 102 (3) ◽  
pp. 762-768 ◽  
Author(s):  
M Nicolet ◽  
M Pinçon-Raymond ◽  
F Rieger
Keyword(s):  
Basal Lamina ◽  
Acetylcholine Receptors ◽  
Muscle Fibers ◽  
Frog Muscle ◽  
Motor Endplate ◽  
Molecular Forms ◽  
Nonionic Detergent ◽  
Plasmic Membrane ◽  
Triton X

After denervation in vivo, the frog cutaneus pectoris muscle can be led to degenerate by sectioning the muscle fibers on both sides of the region rich in motor endplate, leaving, 2 wk later, a muscle bridge containing the basal lamina (BL) sheaths of the muscle fibers (28). This preparation still contains various tissue remnants and some acetylcholine receptor-containing membranes. A further mild extraction by Triton X-100, a nonionic detergent, gives a pure BL sheath preparation, devoid of acetylcholine receptors. At the electron microscope level, this latter preparation is essentially composed of the muscle BL with no attached plasmic membrane and cellular component originating from Schwann cells or macrophages. Acetylcholinesterase is still present in high amounts in this BL sheath preparation. In both preparations, five major molecular forms (18, 14, 11, 6, and 3.5 S) can be identified that have either an asymmetric or a globular character. Their relative amount is found to be very similar in the BL and in the motor endplate-rich region of control muscle. Thus, observations show that all acetylcholinesterase forms can be accumulated in frog muscle BL.

The Filament Lattice of Striated Muscle

1998 ◽  
Vol 78 (2) ◽  
pp. 359-391 ◽  
Author(s):  
BARRY M. MILLMAN
Keyword(s):  
Muscle Contraction ◽  
Structural Changes ◽  
Striated Muscle ◽  
Muscle Fibers ◽  
Lattice Stability ◽  
X Ray Diffraction ◽  
Thin Filaments ◽  
Intact Muscle ◽  
Radial Forces ◽  
Speed Of Shortening

Millman, Barry M. The Filament Lattice of Striated Muscle. Physiol. Rev. 78: 359–391, 1998. — The filament lattice of striated muscle is an overlapping hexagonal array of thick and thin filaments within which muscle contraction takes place. Its structure can be studied by electron microscopy or X-ray diffraction. With the latter technique, structural changes can be monitored during contraction and other physiological conditions. The lattice of intact muscle fibers can change size through osmotic swelling or shrinking or by changing the sarcomere length of the muscle. Similarly, muscle fibers that have been chemically or mechanically skinned can be compressed with bathing solutions containing very large inert polymeric molecules. The effects of lattice change on muscle contraction in vertebrate skeletal and cardiac muscle and in invertebrate striated muscle are reviewed. The force developed, the speed of shortening, and stiffness are compared with structural changes occurring within the lattice. Radial forces between the filaments in the lattice, which can include electrostatic, Van der Waals, entropic, structural, and cross bridge, are assessed for their contributions to lattice stability and to the contraction process.

scholarly journals Thermal Analysis of Bajaj Pulsar Disc Brake

2021 ◽  
pp. 306-312
Author(s):  
K. Kannan ◽  
N. Harikrishnan ◽  
A. Ragul ◽  
P. Vasantha Kumar ◽  
U. Veermani
Keyword(s):  
Thermal Analysis ◽  
Stainless Steel ◽  
Cast Iron ◽  
High Temperature ◽  
Aluminium Alloy ◽  
Maximum Speed ◽  
Disc Brake ◽  
Braking Process ◽  
Rotor Profiles

The disc brake is a device that used for reducing speed or discontinuing the cycle of the vehicle. many times, using the brake for vehicle starts to heat producing during braking process, such that disc brake undergoes breakage due to high temperature. Disc brake design is done through creo 4.0 and analysis is completed by using ANSYS18.1 workbench. The main purpose of this project is to study the Thermal analysis of the Materials for the Cast Iron, Stainless steel and aluminium alloy at various disc rotor profiles. A comparison between the three materials and profile for the Thermal values at maximum speed of the vehicle.

Inhibition of Zn2+-induced potentiation of twitch tension by Ni2+ in frog muscle

1986 ◽  
Vol 64 (5) ◽  
pp. 625-630
Author(s):  
Toshiharu Oba ◽  
Ken Hotta
Keyword(s):  
Action Potential ◽  
Inhibitory Action ◽  
Channel Blocker ◽  
Rana Catesbeiana ◽  
Muscle Fibers ◽  
Frog Muscle ◽  
Duration Of Action ◽  
Ringer’S Solution ◽  
Mechanical Threshold ◽  
T Tubules

Effect of Ni2+ on Zn2+-induced potentiation of twitch tension was studied electrophysiologically in the toe muscle fibers of Rana catesbeiana. The major findings of this investigation are as follows. When 2 mM Ni2+ was applied to fibers in a normal Ringer's solution containing 50 μM Zn2+ (Zn2+ solution), the Zn2+-potentiated twitch tension decreased remarkably to about one-third of that before Ni2+ treatment. This concentration of Ni2+ caused a 23% decrease in the duration of action potential which had been prolonged by Zn2+ (6.61–5.09 ms). Ni2+ (2 mM) added to normal Ringer's solution led to increases of about 30 and 42% in twitch tension and in the duration of action potential, respectively. A slight increase in the mechanical threshold was induced by 2 mM Ni2+. The inhibitory action of Ni2+ on the twitch tension in Zn2+ solution was larger than that in the case of tetanus tension. Diltiazem (40 μM), aCa2+ channel blocker, did not inhibit the twitch tension potentiated in Zn2+ solution. These results suggest that the decrease in Zn2+-potentiated twitch tension by Ni2+ may possibly derive from impairment of the propagation of action potential along the T tubules.

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