Rate of muscle tension development and release under extreme temperatures

1962 ◽  
Vol 19 (5) ◽  
pp. 330-336 ◽  
Author(s):  
David H. Clarke ◽  
Joseph Royce
Keyword(s):  
Muscle Tension ◽  
Extreme Temperatures ◽  
Tension Development

Gradation of isometric tension by different activation rates in motor units of cat flexor carpi radialis muscle

1986 ◽  
Vol 56 (2) ◽  
pp. 494-506 ◽  
Author(s):  
B. R. Botterman ◽  
G. A. Iwamoto ◽  
W. J. Gonyea
Keyword(s):  
Muscle Tension ◽  
Motor Units ◽  
Isometric Tension ◽  
Medial Gastrocnemius ◽  
Potential Contribution ◽  
Tension Development ◽  
Stimulus Interval ◽  
Flexor Carpi Radialis ◽  
Single Motor Units ◽  
Activation Rates

Single motor units of the flexor carpi radialis (FCR) muscle were activated with a series of constant-rate stimulus trains to study the relation between the frequency of activation and isometric tension development (F-T relation). The tension produced by each stimulus train was expressed as a percentage of the maximum tension-time area (Amax) found for a given unit. Between 25 and 75% Amax a clear separation was seen in the rates needed to produce the same relative tension for the F-T curves of slow-twitch (type S) and fast-twitch (type F) units. Over the steepest portion of the F-T curve (25-50% Amax), where tension output was most sensitive to changes in activation rate, type F units required substantially higher stimulation rates (30 pps) to achieve the same relative tension output as type S units. Furthermore, the frequency range that corresponded to the steep portion of the curve was 2.3 times greater for type F units. For both type S and F units, twitch duration was deemed to be an important determinant of the F-T curve, as has been shown previously. A direct continuous relation was seen between the integrated twitch time (ITT) and the stimulus interval needed to produce 50% Amax (r = 0.94, P less than 0.001). Thus, units that had relatively brief twitches required higher activation rates to achieve the same relative percentage of Amax. Comparison of F-T curves from FCR with those derived by other investigators for cat hindlimb units (medial gastrocnemius and peroneus longus) revealed that significant differences in activation rates were needed to produce the same percentage of Amax throughout the midrange of the F-T curve. At 50% Amax, type F units in FCR required activation rates approximately 20 pps higher than type F units in the hindlimb. Type S units in FCR required only slightly higher rates (approximately equal to 5 pps). Based on a number of well-founded assumptions, F-T curves derived from FCR units were used to estimate the potential contribution of rate coding to total muscle tension by type S and F units. This analysis leads to the conclusion that rate modulation is a potentially important factor in the gradation of tension for the FCR muscle.

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.

Epithelial vs. serosal stimulation of tracheal muscle: role of epithelium

1989 ◽  
Vol 67 (6) ◽  
pp. 2522-2526 ◽  
Author(s):  
D. Pavlovic ◽  
M. Fournier ◽  
M. Aubier ◽  
R. Pariente
Keyword(s):  
Time Course ◽  
Muscle Tension ◽  
Active Role ◽  
Force Transducer ◽  
Tension Development ◽  
In Vitro System ◽  
Pharmacological Stimulation ◽  
Stimulation Of

There is evidence implying an active role of airway epithelium in the modulation of bronchomotor tone. To study this phenomenon, we designed an in vitro system allowing pharmacological stimulation of either the inside or outside of the airway lumen. Rat tracheas were excised, cannulated, and their inside and outside perfused independently with Krebs solution. Two hooks were inserted through opposite sides of the tracheal wall, the lower one was attached to a fixed point, while the upper one was connected to a force transducer. Isometric contractions of the tracheal muscle were elicited by carbachol solution perfused in single and cumulative concentrations. In one-half of the preparations the epithelium was mechanically removed. Stimulation of the inside or outside of the trachea produced equal maximal tracheal muscle tension [1.55 +/- 0.14 and 1.2 +/- 0.09 (SE) g in and out, respectively]. The time course of tension development was longer when carbachol was administered inside the trachea: an effect that was abolished when the epithelium was removed. In addition, removal of the epithelium was found 1) to increase the maximal tension irrespective of the route of carbachol perfusion and 2) to increase the sensitivity of the preparation to carbachol stimulation.

Quantitative identification of superoxide anion as a negative inotropic species

1988 ◽  
Vol 255 (1) ◽  
pp. H138-H143 ◽  
Author(s):  
G. M. Schrier ◽  
M. L. Hess
Keyword(s):  
Right Ventricular ◽  
Cardiac Muscle ◽  
Xanthine Oxidase ◽  
Papillary Muscle ◽  
Muscle Function ◽  
Superoxide Anion ◽  
Muscle Tension ◽  
H2o2 Production ◽  
Oxygen Intermediates ◽  
Tension Development

Reduced oxygen intermediates have been shown to directly depress cardiac muscle function at the subcellular, tissue, and whole animal levels. The exact species of reduced oxygen intermediate [superoxide anion radical (O2-.), H2O2, hydroxyl free radical (HO.)] and the concentrations necessary to depress cardiac muscle function have not been quantified. To better understand the role of O2-. and H2O2, we have studied rabbit right ventricular papillary muscle function in the presence of these reduced oxygen intermediates generated by a xanthine-xanthine oxidase system at 37 degrees C. In the presence of xanthine (0.1 mM) and xanthine oxidase (0.02 U/ml), 57.5 +/- 0.85 nmol.l-1.s-1 O2-. and 69.25 +/- 5.3 nmol.l-1.s-1 H2O2 were produced. In the presence of superoxide dismutase (SOD), O2-. was eliminated and H2O2 concentration increased. Catalase effectively eliminated the accumulation of H2O2 without significantly changing the rate of O2-. generation. When applied to isometrically contracting right ventricular papillary muscles, this system, with or without SOD and catalase, had no effect on peak developed tension or +/- dT/dt derived either from length-tension or force-frequency studies. However, when the xanthine oxidase concentration was increased to 0.112 U/ml, the rate of O2-. generation increased to 196.67 +/- 3.26 nmol.l-1.s-1 and H2O2 production increased to 142.19 +/- 9.3 nmol.l-1.s-1 with significant depression of papillary muscle tension development. SOD virtually eliminated O2-. production, whereas H2O2 production increased to 199.48 +/- 9.8 nmol.l-1.s-1 with no effect on papillary muscle tension development.(ABSTRACT TRUNCATED AT 250 WORDS)

A strong constant magnetic field affects muscle tension development in bullfrog neuromuscular preparations

2000 ◽  
Vol 22 (1) ◽  
pp. 53-59 ◽  
Author(s):  
Youko Satow ◽  
Ken'ichi Matsunami ◽  
Takashi Kawashima ◽  
Hirotaka Satake ◽  
Kadrul Huda
Keyword(s):  
Magnetic Field ◽  
Constant Magnetic Field ◽  
Muscle Tension ◽  
Tension Development

Contraction Failure of Skeletal Muscle of Rats Recovering from Critical Illness

1997 ◽  
Vol 92 (2) ◽  
pp. 189-195 ◽  
Author(s):  
Olav E. Rooyackers ◽  
Matthijs K. C. Hesselink ◽  
Anton J. M. Wagenmakers
Keyword(s):  
Skeletal Muscle ◽  
Critical Illness ◽  
Muscle Tension ◽  
High Energy ◽  
High Energy Phosphates ◽  
Maximal Aerobic Capacity ◽  
Tension Development ◽  
Atp Production ◽  
Stimulation Period ◽  
Subsequent Loss

1. Most patients recovering from critical illness experience enhanced fatiguability. Previously we have shown that zymosan-induced critical illness in rats is attended by a decreased mitochondrial content (maximal aerobic capacity) in skeletal muscle. We investigated whether this decrease results in an increased reduction in high-energy phosphates and a subsequent loss of contractility during in situ electrical stimulation in rats recovering from zymosan treatment. 2. Plantar-flexor muscles of the hindlimb were electrically stimulated via the innervating nerve to develop maximal isometric tetanic contraction. 3. Decreased concentrations of ATP were measured in gastrocnemius muscle of zymosan-treated rats, both at rest and after stimulation, in comparison with ad libitum-fed and pair-fed control rats. However, no differences in the stimulation-induced decreases in high-energy phosphate levels and changes in other metabolites, except ADP, were observed between the groups. Tension development in the zymosan-treated rats was, however, about 85% less compared with the pair-fed controls during the whole stimulation period. 4. We conclude that the primary cause of the loss of muscle tension in zymosan-treated rats is an insensitivity of skeletal muscle to stimulation via the nerve. An additional derangement in ATP production is, however, indicated by the comparable decreases in energy substrates during development of a dramatically lower tension.

Prostaglandin and histaminergic mediation of prolonged vasodilation after exercise

1977 ◽  
Vol 233 (1) ◽  
pp. H27-H33 ◽  
Author(s):  
M. L. Morganroth ◽  
E. W. Young ◽  
H. V. Sparks
Keyword(s):  
Blood Flow ◽  
Oxygen Consumption ◽  
Vascular Resistance ◽  
Recovery Period ◽  
Muscle Tension ◽  
Extended Period ◽  
Tension Development ◽  
Flow Duration ◽  
Anesthetized Dogs ◽  
Total Muscle

An extended period of recovery of vascular resistance, far outlasting the recovery period of oxygen consumption, follows exercise of dog skeletal muscle when flow is restricted relative to the intensity of the exercise pattern. The duration of this postexercise prolonged vasodilation is graded and is related to the blood flow, duration of muscle stimulation, fatigue of the muscles, and total muscle tension development. To test whether prolonged vasodilation is mediated by prostaglandins or histamine, the prostaglandin synthetase inhibitors indomethacin or meclofenamate and the antihistamine tripelennamine were administered intravenously to anesthetized dogs between two 20-min exercise bouts of the anterior calf muscles at 4 twitches/s. Blood flow was held constant at approximately 20 ml 100 g-1 min-1, typically resulting in a venous O2 content below 2.0 ml/100 ml during exercise. The duration of vascular resistance recovery was evaluated by measuring the time at which vascular resistance returned to 90% (t90) of the recovery level (mean +/- SE). All the drugs caused a significant decline in the t90, but none reduced the recovery time to that following free-flow exercise, where the t90 is less than 1 min and the return of vascular resistance parallels the return of oxygen consumption to control. Thus, prostaglandin and/or histamine release may be at least partially responsible for prolonged vasodilation.

α1-Adrenergic partial agonists utilize cytosolic Ca2+ more effectively for contraction in aortic smooth muscle

1990 ◽  
Vol 68 (10) ◽  
pp. 1329-1333 ◽  
Author(s):  
Issei Takayanagi ◽  
Shuji Onozuka
Keyword(s):  
Smooth Muscle ◽  
Key Words ◽  
Thoracic Aorta ◽  
Partial Agonist ◽  
Muscle Tension ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Tension Development ◽  
Aortic Smooth Muscle ◽  
Partial Agonists

Fura 2 loaded thoracic aorta strips from rabbits were used. Norepinephrine, phenylephrine, clonidine, and tizanidine induced an increase in cytosolic Ca2+ concentration ([Ca2+]i) and muscle tension in a concentration-dependent manner. A positive correlation between [Ca2+]i and tension development owing to the agonists was noted. The slope of regression lines between [Ca2+]i and tension development for clonidine and tizanidine, α1-adrenergic partial agonists, were significantly steeper than those for norepinephrine and phenylephrine, α1-adrenergic full agonists. The intrinsic activities of the partial agonists obtained from tension development were greater than those from changes in [Ca2+]i. These results suggest that the partial agonists cause a greater muscle tension than the full agonists at the same level of [Ca2+]i.Key words: cytosolic Ca2+ concentration, tension, partial agonist, full agonist,α1-adrenoceptors.

Discharge Patterns of Neurones Supplying Tonic Abdominal Flexor Muscles in the Crayfish

1967 ◽  
Vol 46 (3) ◽  
pp. 393-411
Author(s):  
WILLIAM H. EVOY ◽  
DONALD KENNEDY ◽  
DONALD M. WILSON
Keyword(s):  
Time Constant ◽  
Muscle Tension ◽  
Simultaneous Recording ◽  
Spontaneous Discharge ◽  
Tension Development ◽  
Flexor Muscles ◽  
Visible Effect ◽  
Discharge Patterns ◽  
Short Time ◽  
Coupling Mechanisms

1. The discharge patterns of tonic flexor motoneurones in the crayfish abdomen have been investigated by simultaneous recording from several nerve roots. The five flexor motoneurones supplying each segment are serially homologous, smaller units have higher discharge frequencies, and the excitability of a given unit is generally higher in more caudal ganglia. 2. Even the smallest axons are capable of generating substantial muscle tension at their spontaneous discharge frequencies. Tension development is extremely tonic. Single motor impulses are without effect, latencies are long, and the frequency/tension relation is steep. 3. The inhibitory axon to each flexor discharges during ‘extension’ reflexes, but has no visible effect upon relaxation time, or upon the response to subsequent excitation. Inhibitory impulses do not relax previously unexcited muscle. 4. Phase histograms for the discharge of pairs of homologous or non-homologous efferent axons across a single ganglion, within the same root, and between adjacent ganglia have revealed several coupling mechanisms. One is mediated by short time-constant electrotonic junctions between bilaterally paired inhibitory axons. The second involves weaker, more generalized interactions of longer time-constant between non-homologous axons. The third is brought about by common presynaptic sources of excitation. Inputs tend to be common for homologues in adjacent ganglia rather than for non-homologues in a single ganglion, a finding consistent with the selectivity shown by central interneurones in their effects upon motoneurones.

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