Effect of low extracellular calcium and ryanodine on muscle contraction of the mouse during postnatal development

1991 ◽  
Vol 69 (9) ◽  
pp. 1294-1300 ◽  
Author(s):  
Josette Dangain ◽  
Ian R. Neering
Keyword(s):  
Time Course ◽  
Age Groups ◽  
Isometric Tension ◽  
Muscle Fibres ◽  
Gradual Change ◽  
Free Solution ◽  
Cobalt Ions ◽  
Contraction Speed ◽  
Single Twitch ◽  
Isometric Twitch

We have examined the effects of low Ca2+ solutions, Co2+, and ryanodine on the isometric tension and contraction speed of isolated, developing mouse EDL muscles. Twitch responses of young muscles (7–14 days postnatal) were more sensitive to lowered [Ca2+]0 than those of more fully developed muscles (22–35 days postnatal). Responses of EDL muscles from a middle-aged group (15–21 days postnatal) were intermediate between the two other groups. Overall, the time course of contraction in a single twitch was accelerated by low [Ca2+]o. Ca2+-free solution induced a 7.95 and 9.25 mV depolarization in young and "old" muscle fibres, respectively. The presence of cobalt ions (5 mM) in the Krebs solution had a similar effect as Ca2+-free Krebs in terms of reduction of the isometric twitch and tetanic tensions of EDL muscles from the various age groups. In contrast, the shortening of the contraction time seen with Ca2+-free solution did not take place following exposure to Co2+-containing solutions. Finally, young (7–14 days postnatal) muscles were less sensitive to the inhibitory action of ryanodine on the twitch compared with more fully developed muscles (22–35 days postnatal). Taken together, our results indicate that from birth to maturity, there is a gradual change in the spectrum of calcium utilization for the contractile process.Key words: mammalian muscle, calcium, development, ryanodine, contraction, sarcoplasmic reticulum.

Neuromuscular Transmission in the Longitudinal Layer of Somatic Muscle in the Earthworm

1969 ◽  
Vol 50 (2) ◽  
pp. 417-430
Author(s):  
T. HIDAKA ◽  
Y. ITO ◽  
H. KURIYAMA ◽  
N. TASHIRO
Keyword(s):  
Time Course ◽  
Longitudinal Muscle ◽  
Chloride Concentration ◽  
Reversal Potential ◽  
Membrane Conductance ◽  
Equilibrium Potential ◽  
Muscle Fibres ◽  
Free Solution ◽  
Excitatory Junction Potentials ◽  
Potential Level

1. The properties of the miniature inhibitory junction potentials (M.I.J.P.) and the inhibitory junction potentials (I.J.P.) elicited by nerve stimulation were investigated in longitudinal muscle fibres of the earthworm. 2. Histograms of the amplitudes(mean,0.71mV.) and the intervals (mean, 101 msec.) of the M.I.J.P. showed skew curves. 3. The polarity of the M.I.J.P. was reversed at about -60 mV. When the external chloride was substituted by glutamate the M.I.J.P. disappeared as an external chloride concentration of 15-20 mM, and further reduction reversed their polarity. 4. Picrotoxin blocked generation of the M.I.J.P. and the I.J.P. 5. The cross-over point of the current-voltage relation curves, with and without presence of GABA, occurred at a membrane potential of -54 mV. in potassium-free solution, and at -56 mV. in potassium-excess solution. 6. Iontophoretic application of GABA produced slow hyperpolarization. The equilibrium potential of the GABA-potential was about -60 mV. During the time course of the GABA-potentials an increase in the membrane conductance was observed. 7. Miniature excitatory junction potentials (M.E.J.P.) and excitatory junction potentials (E.J.P.) could be recorded from the longitudinal muscle, but the M.E.J.P. were rare. 8. D-tubocurarine, but not atropine, completely blocked the M.E.J.P. and E.J.P. Prostigmine enhanced their amplitude and duration. 9. The reversal potential level for the E.J.P. was about 0 mV. Sodium-free solution lowered the reversal potential level for the M.E.J.P. to -20 mV.

Myocardial energetics during isometric twitch contractions of cat papillary muscle

1979 ◽  
Vol 236 (2) ◽  
pp. H244-H253 ◽  
Author(s):  
G. Cooper
Keyword(s):  
Linear Relationship ◽  
Isometric Tension ◽  
Active Tension ◽  
Continuous Increase ◽  
Time Integral ◽  
Myocardial Energetics ◽  
Isometric Twitch ◽  
Slack Length ◽  
Energy Dependent ◽  
Complete Contraction

During myocardial tetanus, when activation is maximum and constant, there is a linear relationship throughout contraction between oxygen consumption (MVo2) and the cumulative product of active tension and time (integral of AT). The goal of this study was to determine the relation of MVo2 to integral of AT during isometric myocardial twitch contractions. Ten right ventricular cat papillary muscles were studied in a flow respirometer. MVo2 was determined during contractions unloaded from Lmax to a slack length at successive 100-ms intervals after stimulation. In contrast to the linear relationship observed during tetanus, MVo2/integral of AT varied during twitch contractions: when the muscles were made slack 100 ms after stimulation MVo2/integral of AT was 389 +/- 51 (SE) (nl of O2/mg of dry muscle)/(N of active tension/mm2.s of active tension). This value was 94 +/- 7 at peak active tension and was constant thereafter. There was a continuous increase in cumulative MVo2 as integral of AT increased; before integral of AT began, MVo2 was 0.41 +/- 0.04 (nl of O2/mg)/contraction at Lmax and 0.22 +/- 0.04 at a slack length; at peak isometric tension MVo2 was 1.84 +/- 0.19; for a complete contraction MVo2 was 2.89 +/- 0.25. These data support two concepts 1) activation energy is small and dependent on initial length and tension; and 2) integral of AT is variably energy dependent throughout the entire isometric twitch contraction.

scholarly journals The effects of temperature and pH on the contractile properties of skinned muscle fibres from the terrapin, Pseudemys scripta elegans

1987 ◽  
Vol 128 (1) ◽  
pp. 87-105 ◽  
Author(s):  
G. Mutungi ◽  
I. A. Johnston
Keyword(s):  
Temperature Dependence ◽  
Dark Field ◽  
Isometric Tension ◽  
Contractile Properties ◽  
Test Method ◽  
Fibre Types ◽  
Muscle Fibres ◽  
Contraction Velocity ◽  
Pseudemys Scripta

Fibre types in the iliofibularis muscle of the freshwater terrapin Pseudemys scripta elegans have been characterized on the basis of their histochemical characteristics, nerve endings and contractile properties. Three types of focally innervated fibres are present, corresponding to the fast glycolytic (Fg), fast oxidative glycolytic (FOG) and slow oxidative (SO) fibre types of other vertebrates. Single fibres or small bundles of fibres representing each histochemical type were identified on the basis of their light scattering properties under dark-field illumination. Fibres were detergent-skinned using Brij 58, and their maximum isometric tension (P0) and unloaded contraction velocity (V0) were determined by the slack test method. At 15 degrees C, fast glycolytic fibres generated maximum isometric tensions of 184 +/− 5 kNm-2 and V0 values of 5.5 +/− 0.3 muscle lengths per second (L0s-1). Slow oxidative fibres produced tensions of 70.6 +/− 3 kNm-2 and had V0 values of 1.3 L0s-1. Tensions and V0 values of fast oxidative glycolytic fibres were between those of Fg and SO fibres. The force-velocity (P-V) characteristics of slow oxidative fibres were studied at 5 degrees and 15 degrees C. Points below 0.6 P0 on the curves could be fitted by a linear form of Hill's equation. Maximum contraction velocities (Vmax) extrapolated from the P-V relationship were 0.62 L0s-1 at 5 degrees C and 0.91 L0s-1 at 15 degrees C. The curvature of the P-V relationship was relatively independent of temperature over the range 5 to 15 degrees C. Values for Hill's constant a/P0 were 0.29 and 0.33 at 5 degrees C and 15 degrees C, respectively. The temperature dependence of P0 and contraction velocity at near zero load (Vi) were studied at constant pH, and under conditions designed to simulate the changes in intracellular pH which occur with temperature in vivo (delta pH/delta T = −0.0186). Changes in pH in the range 6.6 to 7.8 had no effect on either tension or Vi at temperatures between 0 degrees and 20 degrees C. However, below and above this pH range, both tension and Vi were depressed. It is concluded that pH changes within the normal physiological range (6.7-7.8) have no effect on the temperature dependence of P0 and Vi.

Neuromuscular Physiology of the Longitudinal Muscle of the Earthworm, Lumbricus Terrestris

1974 ◽  
Vol 60 (2) ◽  
pp. 453-467
Author(s):  
C. D. DREWES ◽  
R. A. PAX
Keyword(s):  
Time Course ◽  
Longitudinal Muscle ◽  
Lumbricus Terrestris ◽  
Single Pulse ◽  
Repetitive Stimulation ◽  
Muscle Fibres ◽  
Mechanical Responses ◽  
Segmental Nerve ◽  
Earthworm Lumbricus ◽  
Stimulation Of

1. Patterns of innervation of the longitudinal muscle of the earthworm, Lumbricus terrestris, were examined electrophysiologically. 2. The longitudinal musculature of a segment is innervated by relatively few axons, a fast and slow axon being present in segmental nerve I and in the double nerve, segmental nerve II-III. 3. Single-pulse stimulation of the fast axon produces large external muscle potentials and small twitch-like contractions, which with repetitive stimulation are antifacilitating. 4. Repetitive stimulation of the slow axon produces large, slowly developing and sustained mechanical responses, with electrical and mechanical responses showing summation and facilitation. 5. The amplitude and time course of slow mechanical responses are related to the frequency of stimulation. 6. Individual longitudinal muscle fibres are innervated by either the fast or slow axon in a segmental nerve, or by both fast and slow axons. 7. No evidence was found for peripheral inhibitory innervation of the longitudinal muscle.

Potentiation of Neuromuscular Transmission by an Octopaminergic Neurone in the Locust

1979 ◽  
Vol 79 (1) ◽  
pp. 169-190 ◽  
Author(s):  
MICHAEL O'SHEA ◽  
PETER D. EVANS
Keyword(s):  
Indirect Effects ◽  
Neuromuscular Transmission ◽  
Time Course ◽  
Muscle Tone ◽  
Muscle Tension ◽  
Presynaptic Receptors ◽  
Extensor Muscle ◽  
Muscle Membrane ◽  
Muscle Fibres ◽  
Central Synapses

1. Spikes in the octopaminergic dorsal unpaired median (DUM) neurone which innervates the extensor tibiae muscle of the locust metathoracic leg (DUMETi) produce direct and indirect effects on muscle tension. 2. Direct effects include a slowing of an intrinsic rhythm of contraction and relaxation, a relaxation of muscle tone and a small hyperpolarization of the muscle membrane potential. The latter two effects are weak and variable. All three effects are mimicked by superfusion of octopamine and are mediated by octopamine receptors on the muscle fibres. 3. Indirect effects are found when the DUMETi neurone is stimulated at the same time as the motoneurones innervating the extensor muscle. They include (a) potentiation of tension generated in the extensor muscle by spikes in the slow excitatory motoneurone (SETi), (b) reduction in duration of each twitch contraction generated by SETi due to an increase in the rate at which the muscle relaxes, (c) increase in the amplitude of the synaptic potential generated by SETi. These various effects have a time course of several minutes and far outlast the duration of DUMETi stimulation. They can be mimicked by superfusion of octopamine. 4. The effect of DUMETi on neuromuscular transmission is mediated by receptors with a high affinity for octopamine located both on the muscle and on the terminals of the slow motoneurone. The presence of the presynaptic receptors is revealed by the increase in the frequency of spontaneous miniature end plate potentials recorded in the muscle in the presence of octopamine. 5. DUMETi is a member of a group of similar aminergic neurones and it is suggested that they may share a role in modulating transmission at peripheral neuromuscular synapses, and possibly central synapses.

Average but not continuous speed match between motoneurons and muscle units of rat tibialis anterior

1993 ◽  
Vol 70 (4) ◽  
pp. 1300-1306 ◽  
Author(s):  
R. Bakels ◽  
D. Kernell
Keyword(s):  
Tibialis Anterior ◽  
Time Course ◽  
Muscle Fibers ◽  
Total Duration ◽  
Medial Gastrocnemius ◽  
Tetanic Force ◽  
Time To Peak ◽  
Time Courses ◽  
Isometric Twitch ◽  
Fatigue Sensitivity

1. Properties of single motoneuron/muscle-unit combinations were determined for tibialis anterior (TA) in rats anesthetized with pentobarbital. The TA observations were systematically compared with those obtained earlier by the use of the same techniques from rat medial gastrocnemius (MG). 2. TA motoneurons were investigated with regard to afterhyperpolarization (AHP; total duration 32-74 ms, amplitude 0.39-4.96 mV) and axonal conduction velocity (41-79 m/s). TA muscle-unit measurements included the time course of the isometric twitch (time-to-peak force 10.8-18.0 ms; total duration 42-92 ms), the maximum tetanic force (22-217 mN), and a measure of fatigue sensitivity (fatigue index 5-100%). The range of twitch and AHP durations ("speed range") was markedly smaller in the present TA material than for MG. 3. The mean duration of the TA motoneuronal AHP (49 +/- 8 ms, mean +/- SD) was close to that of its muscle-unit twitch (56 +/- 12 ms). Thus an "average" speed match existed between TA motoneurons and their muscle fibers. 4. For TA there was no correlation between the time courses of AHP and twitch. Thus there was for TA no "continuous" speed match between the motoneurons and their muscle fibers. 5. For TA twitches or AHPs studied separately, there was a significant correlation between different time course measures. Furthermore, compared with TA units having relatively fast twitches, those with slower twitches tended to show 1) a smaller maximum tetanic force and 2) a greater AHP amplitude. Fatigue-resistant units tended to have slower twitches than fatigue-sensitive ones.(ABSTRACT TRUNCATED AT 250 WORDS)

Stretch overload-induced satellite cell activation in slow tonic muscle from adult and aged Japanese quail

1996 ◽  
Vol 270 (2) ◽  
pp. C578-C584 ◽  
Author(s):  
J. A. Carson ◽  
S. E. Alway
Keyword(s):  
Japanese Quail ◽  
Satellite Cells ◽  
Time Course ◽  
Cell Activation ◽  
Age Groups ◽  
Fiber Formation ◽  
Left Wing ◽  
Old Japanese ◽  
Fiber Number ◽  
Incorporated Brdu

Stretch overload-induced activation of satellite cells in the anterior latissimus dorsi (ALD) muscle was examined in full-grown adult (12 wk old) and aged (90 wk old) Japanese quail. 5'-Bromo-2'-deoxyuridine (BrdU) constant-release pellets (0.22 mg BrdU.g body wt-1.day-1) were implanted subcutaneously before weighting the left wing of each bird. Nuclei that incorporated BrdU were localized by immunohistochemistry after 1 or 2 wk of stretch overload. Total fiber number was quantified by counting all fibers in a histological cross section from the midbelly of the ALD. Aging reduced increases in ALD mass and fiber number during 2 wk of stretch overload. Fiber proliferation in the ALD of aged birds also demonstrated an altered time course. The percentage of BrdU-positive nuclei associated with muscle fibers and the percentage of fibers associated with BrdU-positive nuclei did not differ between age groups. The altered time course of new fiber formation in the ALD of aged birds during 2 wk of stretch overload does not appear to be related to the capability to activate satellite cells.

Enhanced contractility during relaxation of cat papillary muscle

1975 ◽  
Vol 228 (6) ◽  
pp. 1708-1716 ◽  
Author(s):  
BG Bass
Keyword(s):  
Papillary Muscle ◽  
Time Course ◽  
Isometric Tension ◽  
Contractile Element ◽  
Cat Papillary Muscle ◽  
Postextrasystolic Potentiation ◽  
Peak Tension ◽  
Time To Peak ◽  
In Series ◽  
Antecedent Control

Contractility during relaxation of isometric tension was studied in isolated, electrically driven cat papillary muscle by interpolation of test extrasystoles, all of whichpartially fused with their antecedent (control) contractions, were separated by computer from the fused contractions and then analyzed. The time course of the restitutionof contractility during relaxation was defined by plotting maximal positive dT/dt andtime-to-peak tension of the computer-separated extrasystole versus delay preceding the extrasystole. The dT/dt and time-to-peak tension, which steadily decline with progressive prematurity between contractions, both increase again during late relaxation, become progressively greater still earlier in relaxation, peak shortly after peak isometric tension, and then again decline. This phase of an apparently enhanced contractilityduring relaxation is depressed in low Ca'++ and is transmitted into the postextrasystolic period (in which it is superimposed on the usual postextrasystolic potentiation). The possible contributions of variations in series-elastic component and contractile-element lengths, actionpotential characteristics, and other factors on contractility during relaxation are discussed. It is suggested that enhanced contractility during relaxation may also be related in part to the decay of the intracellular free Ca'++ transient.

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