Tension development of glycerinated insect muscle fibres as a measure of the conformational state of the myosin

1966 ◽  
Vol 24 (4) ◽  
pp. 526-530 ◽  
Author(s):  
R.A. Chaplain
Keyword(s):  
Conformational State ◽  
Muscle Fibres ◽  
Tension Development ◽  
Insect Muscle

The Effects of Acclimation Temperature on a Neuromuscular System of the Crayfish, Astacus Leptodactylus

1979 ◽  
Vol 78 (1) ◽  
pp. 281-293
Author(s):  
MIKKO HARRI ◽  
ERNST FLOREY
Keyword(s):  
Membrane Lipids ◽  
Characteristic Temperature ◽  
Resting Membrane Potential ◽  
Acclimation Temperature ◽  
Muscle Fibres ◽  
Astacus Leptodactylus ◽  
Tension Development ◽  
Temperature Range ◽  
Wide Range ◽  
Warm Acclimation

1. Crayfish, Astacus leptodactylus, were acclimated to 12 °C and to 25 °C. Nerve muscle preparations (closer muscle of walking legs) were subjected to temperatures ranging from 6 to 32 °C. 2. The resting membrane potential of muscle fibres was found to increase with temperature in a linear manner, but with a change in slope at around 170 in cold-acclimated preparations, and around 24 °C in warm-acclimated ones. 3. Temperature acclimation shifted the temperature range of maximal amplitudes of fast and slow e.j.p.s toward the acclimation temperature. Optimal facilitation of slow e.j.p.s also occurred near the respective acclimation temperature. 4. E.j.p. decay time is nearly independent of temperature in the upper temperature range but increases steeply when the temperature falls below a critical range around 17 °C in preparations from cold-acclimated animals, and around 22 °C after acclimation to 25 °C. 5. Peak depolarizations reached by summating facilitated e.j.p.s are conspicuously independent of temperature over a wide range (slow and fast e.j.p.s of cold-acclimated preparations, fast e.j.p.s of warm-acclimated ones) which extends to higher temperatures after warm acclimation in the case of fast e.j.p.s. In warm-acclimated preparations the peak depolarization of slow e.j.p.s first falls then rises and falls again as the temperature increases from 8 to 32 °C. 6. Tension development elicited by stimulation of the slow axon at a given frequency reaches maximal values at the lower end of the temperature range in cold-acclimated preparations. The maximum is shifted towards 20 °C after warm acclimation. Fast contractions decline with temperature; possible acclimation effects are masked by the great lability of fast contractions in warm-acclimated preparations. 7. It is suggested that changes in the composition of membrane lipids may be responsible for the effects of acclimation on the electrical parameters and their characteristic temperature dependence.

Control of tension development in scallop muscle fibres with foreign regulatory light chains

Nature ◽  
1980 ◽  
Vol 286 (5773) ◽  
pp. 626-628 ◽  
Author(s):  
R. M. Simmons ◽  
A. G. Szent-Györgyi
Keyword(s):  
Light Chains ◽  
Muscle Fibres ◽  
Tension Development ◽  
Regulatory Light Chains

Local anaesthetics inhibit tension development and Nile blue fluorescence signals in frog muscle fibres

Nature ◽  
1979 ◽  
Vol 277 (5695) ◽  
pp. 400-402 ◽  
Author(s):  
CARLO CAPUTO ◽  
JULIO VERGARA ◽  
FRANCISCO BEZANILLA
Keyword(s):  
Nile Blue ◽  
Local Anaesthetics ◽  
Frog Muscle ◽  
Muscle Fibres ◽  
Blue Fluorescence ◽  
Tension Development

scholarly journals Effect of lanthanum ions on neuromuscular transmission in insects

1983 ◽  
Vol 107 (1) ◽  
pp. 405-414
Author(s):  
H. Washio ◽  
T. Miyamoto
Keyword(s):  
Neuromuscular Transmission ◽  
Nerve Impulse ◽  
Postsynaptic Membrane ◽  
Muscle Fibres ◽  
Excitatory Postsynaptic Potential ◽  
Bathing Medium ◽  
Insect Muscle ◽  
Lanthanum Ions ◽  
Postsynaptic Action ◽  
Ventral Muscle

The effect of extracellular lanthanum on neuromuscular transmission was studied in cockroach leg muscle and larval mealworm ventral muscle by means of microelectrodes. Miniature excitatory postsynaptic potential (MEPSP) frequency was markedly increased after lanthanum was added, in the presence and absence of calcium. The potentiation by La3+ was suppressed in a high Ca2+ saline and enhanced in the absence of Ca2+. Lanthanum ions blocked neuromuscular transmission at a concentration as low as 0.1 mM. The quantal content estimated by the failure method was reduced by 80% in the presence of 0.1 mM-La3+. The reduction in the EPSP amplitude by La3+ may be due to a decrease in the amount of transmitter released by a nerve impulse. The response to L-glutamate applied iontophoretically was also reduced in the presence of La3+. It seems unlikely that La3+ and L-glutamate were competing for a common binding site on the postsynaptic membrane since the apparent maximum of the dose-response curve for glutamate-induced depolarization was reduced in the presence of La3+. External recording of MEPSPs showed that adding lanthanum to the bathing medium increased the time constant of decay of the potential. These results suggest that lanthanum does indeed have a postsynaptic action in addition to its prejunctional action in insect muscle fibres.

scholarly journals THE MODULATORY EFFECTS OF SEROTONIN, NEUROPEPTIDE F1 AND PROCTOLIN ON THE RECEPTOR MUSCLES OF THE LOBSTER ABDOMINAL STRETCH RECEPTOR AND THEIR EXOSKELETAL MUSCLE HOMOLOGUES

1993 ◽  
Vol 174 (1) ◽  
pp. 363-374
Author(s):  
V. M. Pasztor ◽  
L. B. Golas
Keyword(s):  
Muscle Fibres ◽  
Sensory Afferents ◽  
Tension Development ◽  
Sensory Neurones ◽  
Multiple Loci ◽  
Receptor Organ ◽  
Two Measures ◽  
Low Incidence ◽  
Passive Stretch ◽  
Receptor Muscle

The muscle receptor organ (MRO) of the lobster is a complex proprioceptive system lying in parallel with the axial extensor musculature. Two peripherally located sensory neurones extend stretch-sensitive dendrites into individual receptor muscle strands one tonic (RM1) and one phasic (RM2). Previous studies have shown that the sensitivity of the sensory neurones to passive stretch could be enhanced by serotonin and proctolin. Here we show that the receptor muscles and their exoskeletal muscle homologues are also responsive to serotonin, proctolin and, in addition, to neuropeptide F1 (TNRNFLRF-NH2). Two measures of motor performance were enhanced by all three neurohormones: EJP amplitude and nerve-evoked tension development. Serotonin was the most effective modulator of both tonic and phasic muscles. F1 had powerful effects on the phasic extensor muscle. A low incidence of tonic muscle fibres with synapses responding to the neurohormones suggests that there are distinct populations of synapses: those sensitive to specific modulators and others that are insensitive. These findings, taken together with the enhancing effects of modulation on the primary sensory afferents, suggest that circulating neurohormones may act at multiple loci in the MRO system in a concerted and hormone-specific manner to alter the flow of proprioceptive feedback.

Cellular insertion of primary and secondary myotubes in embryonic rat muscles

Development ◽  
1989 ◽  
Vol 107 (2) ◽  
pp. 243-251
Author(s):  
M.J. Duxson ◽  
Y. Usson
Keyword(s):  
Ultrastructural Study ◽  
Muscle Tension ◽  
Electrical Coupling ◽  
Muscle Fibres ◽  
Tension Development ◽  
End To End ◽  
Developing Muscle ◽  
Two Populations ◽  
Unique Relationship ◽  
Adhering Junctions

Mammalian muscles develop from two populations of myotubes; primary myotubes appear first and are few in number; secondary myotubes appear later and form most of the muscle fibres. We have made an ultrastructural study to investigate how primary and secondary myotubes in embryonic rat muscles transmit tension during the period of their development. Primary myotubes extend from end to end of the muscle from the earliest times, and attach directly to the tendon. In contrast, newly formed secondary myotubes are short cells which insert solely into the primary myotubes by a series of complex interdigitating folds along which adhering junctions occur. As the secondary myotubes lengthen and mature, their insertion is progressively transferred from the primary myotube to the tendon proper. We suggest that this variable insertion of immature secondary myotubes, combined with complex patterns of innervation and electrical coupling in developing muscle, makes it difficult to predict the overall contribution of secondary myotubes to muscle tension development. This work extends other studies showing the unique relationship between a primary myotube and its associated secondary myotubes, indicating that these may constitute a developmental compartment.

Physiological features of the opercularis muscle and their effects on vibration sensitivity in the bullfrog Rana catesbeiana

1987 ◽  
Vol 131 (1) ◽  
pp. 189-204
Author(s):  
T. E. Hetherington
Keyword(s):  
Inner Ear ◽  
Slow Rate ◽  
Rana Catesbeiana ◽  
Muscle Tension ◽  
Isometric Tension ◽  
Sensory Function ◽  
Morphological Evidence ◽  
Muscle Fibres ◽  
Ground Vibrations ◽  
Tension Development

The amphibian opercularis muscle connects a movable otic element (the operculum) to the pectoral girdle and can act in reception of ground vibrations. Various physiological parameters of the opercularis muscle of the bullfrog Rana catesbeiana were measured and compared with similar measurements on the iliofibularis muscle of the hindlimb. The opercularis muscle is a very slowly contracting muscle, with a Vmax of 1.81 muscle lengths s-1 compared to a Vmax of 6.24 muscle lengths s-1 for the iliofibularis muscle. The opercularis muscle develops tension slowly, taking about 10 s to attain maximum isometric tension when stimulated at 100 Hz. The muscle can retain high levels of tension for several minutes, and following stimulation has a time to half-relaxation of about 4–6 s. The slow velocity of contraction, slow rate of tension development, fatigue-resistance and slow rate of relaxation of the opercularis muscle support morphological evidence that it consists mostly of tonic muscle fibres. Experiments were also made to examine the effects of muscle tension on reception of ground vibrations as measured by inner ear microphonics. Severing the nerve supplying the opercularis muscle produced slight decreases of no more than 2 dB in responses to vibrations from 25 to 200 Hz. Artificial stimulation of the opercularis muscle after severing the nerve supplying the muscle increased responses to vibration across the entire frequency range. Higher tension levels produced greater increases in responses; at the highest tensions used (about 120 kN m-2) responses were increased by as much as 4.5 dB. The opercularis muscle is therefore specialized for slow but prolonged contractions, and tension is important in its sensory function. A tensed opercularis muscle appears to transmit faithfully motion of the forelimb, produced by vibrations, to the operculum such that the latter moves relative to the inner ear fluids.

Influence of crank rate on the slow component of pulmonary O2 uptake during heavy arm-crank exercise

2006 ◽  
Vol 31 (3) ◽  
pp. 292-301 ◽  
Author(s):  
Paul M Smith ◽  
Eilidh McCrindle ◽  
Mike Doherty ◽  
Michael J Price ◽  
Andrew M Jones
Keyword(s):  
Oxygen Uptake ◽  
Peak Power ◽  
Slow Component ◽  
Work Rate ◽  
Rating Of Perceived Exertion ◽  
Muscle Fibres ◽  
External Work ◽  
Tension Development ◽  
Significant Difference ◽  
The Mean

The principal aim of this study was to examine the influence of variations in crank rate on the slow component of the pulmonary oxygen uptake ([Formula: see text]O2) response to heavy-intensity arm-crank ergometry (ACE). We hypothesized that, for the same external work rate, a higher crank rate would elicit a greater amplitude of the [Formula: see text]O2 "slow component". Eleven healthy males (mean (± SD) age, 25 (±6) y; body mass, 89.1 (±10.7) kg; ACE [Formula: see text]O2 peak, 3.36 (±0.47) L·min-1) volunteered to participate. The subjects initially completed an incremental exercise test for the determination of [Formula: see text]O2 peak and peak power on an electrically braked arm ergometer. Subsequently, they completed "step" transitions from an unloaded baseline to a work rate requiring 70% of peak power: 2 at a crank rate of 50 r·min-1 (LO) and 2 at a crank rate of 90 r·min-1 (HI). Pulmonary gas exchange was measured on a breath-by-breath basis and [Formula: see text]O2 kinetics were evaluated from the mean response to each condition using non-linear regression techniques. In contradiction to our hypothesis, the [Formula: see text]O2 slow component was significantly greater at 50 r·min-1 than at 90 r·min-1 (LO: 0.60 ± 0.30 vs. HI: 0.47 ± 0.21 L·min-1; p < 0.05). The mean value for the localized rating of perceived exertion was also higher at 50 r·min-1 than at 90 r·min-1 (LO: 16.7 ± 1.4 vs. HI: 15.2 ± 1.3; p < 0.05), but there was no significant difference in end-exercise blood lactate concentration. It is possible that differences in muscle tension development and blood flow resulted in a greater contribution of "low-efficiency" type II muscle fibres to force production at the lower crank rate in ACE, and that this was linked to the greater [Formula: see text]O2 slow component. However, other factors such as greater isometric contraction of the muscles of the trunk and legs at the lower crank rate might also be implicated.Key words: O2 kinetics, [Formula: see text]O2 slow component, fibre recruitment, oxygen uptake.

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