Isometric contractile properties and instantaneous stiffness of amphibian skeletal muscle in the temperature range from 0 to 20 °C

1981 ◽  
Vol 59 (6) ◽  
pp. 548-554 ◽  
Author(s):  
Bernard H. Bressler
Keyword(s):  
Relaxation Time ◽  
Elevated Temperatures ◽  
Bufo Bufo ◽  
Contractile Properties ◽  
Temperature Range ◽  
Time To Peak ◽  
Intracellular Ca ◽  
Cross Bridges ◽  
Isometric Twitch ◽  
Toad Bufo

The isometric contractile properties of frog (Rana pipiens) and toad (Bufo bufo) sartorii have been studied over the temperature range from 0 to 20 °C. The isometric twitch tension was found to vary considerably between these two species and between muscles in the same species. Between 0 and 4 °C ther was very little change in maximum isometric twitch tension. Between 4 and 12 °C several muscles from frog or toad showed a potentiation of twitch tension whereas others showed a decline. Over this temperature range the toad sartorii consistently demonstrated a greater potentiation. By 12 °C a steady decline in twitch tension in both muscles was seen as the temperature approached 20 °C. The maximum isometric tetanic tension recorded between 18 and 20 °C increased fractionally to an average of 1.504 ± 0.029 (n = 4) for frog sartorii and to 1.377 ± 0.008 (n = 5) for toad sartorii. The time to peak twitch tension and the half-relaxation time decreased markedly with an increase in temperature. Moreover, the half-relaxation time was reduced by a greater proportion than the time to peak twitch tension. Measurements of instantaneous stiffness by controlled velocity releases from the plateau of isometric tetani revealed that the large increase in isometric tetanus tension as the muscle was warmed was not accompanied by a corresponding increase in the total number of active cross-bridges. The possibility that a decreased availability of intracellular Ca2+ ions at the contractile sites contributing to the fall of isometric twitch tension at elevated temperatures is discussed. The possibility exists that at elevated temperatures a change in the intrinsic-contractile ability of the muscle occurs which produces an increased tension per cross-bridge.

Functional significance of compensatory overloaded rat fast muscle

1982 ◽  
Vol 52 (2) ◽  
pp. 473-478 ◽  
Author(s):  
R. R. Roy ◽  
I. D. Meadows ◽  
K. M. Baldwin ◽  
V. R. Edgerton
Keyword(s):  
Biochemical Properties ◽  
Slow Muscle ◽  
Repetitive Stimulation ◽  
Contractile Properties ◽  
Sectional Area ◽  
Shortening Velocity ◽  
Cross Sectional ◽  
Time To Peak ◽  
Isometric Twitch

Chronic overload of a skeletal muscle by removing its synergists produces hypertrophy and marked changes in its metabolic and biochemical properties. In this study alterations in the contractile properties of the plantaris 12–14 wk after bilateral removal of the soleus and gastrocnemius were investigated. In situ isometric and isotonic contractile properties of overloaded plantaris (OP), normal plantaris (NP), and normal soleus (NS) were tested at 33 +/- 1 degree C. Op were 97% heavier than NP and produced 43 and 46% higher twitch (Pt) and tetanic (Po) tensions. However, NP produced more tension per cross-sectional area than OP (mean 26.2 vs. 21.6 N/cm2; P less than 0.001). Isometric twitch time to peak tension (TPT) and half-relaxation time (1/2RT) were significantly longer in OP (mean 36.4 vs. 32.5 ms and 23.9 vs. 18.4 ms). Mean maximum shortening velocity (Vmax, mm/s per 1,000 sarcomeres) were 34.1 for NP and 18.1 for OP (P less than 0.001). The degree of conversion toward the Vmax of NS was 74% compared with only 19 and 14% for TPT and 1/2RT. OP produced a higher proportion of Po at a given stimulation frequency than NP and showed less fatigue than NP after repetitive stimulation. Chronic overload of the fast plantaris modified to varying degrees the contractile properties studied toward that resembling a slow muscle. Although the maximum tension of OP was markedly enhanced it was not in proportion to the increase in muscle mass.

Strength and Contractile Adaptations in the Human Triceps Surae after Isotonic Exercise

1993 ◽  
Vol 2 (2) ◽  
pp. 104-114 ◽  
Author(s):  
Crayton L. Moss ◽  
Scott Grimmer
Keyword(s):  
Relaxation Time ◽  
Repeated Measures ◽  
Peak Force ◽  
Contractile Properties ◽  
Triceps Surae ◽  
Type I ◽  
Muscle Twitch ◽  
Time To Peak ◽  
High Repetition ◽  
Isotonic Exercise

The purpose of this study was to determine whether twitch contractile properties and strength of the triceps surae could be altered by 8 weeks of low-repetition or high-repetition isotonic exercise. Subjects were randomly assigned to either the low- or high-repetition group. Before- and after-training measurements were recorded for strength and contractile properties. The contractile variables of the muscle twitch were latency, time to peak force, peak force, half-contraction time, and half-relaxation time. Strength measurements were determined utilizing a one repetition maximal (1-RM) heel-raise testing device. A two-way ANOVA with repeated measures was used to test the effect of training on each variable. Both groups showed a significant increase in 1-RM and half-relaxation time and a decrease in electrical stimulation current after the 8-week training period. It was concluded that if high-repetition exercises develop slow-twitch Type I muscle fibers and low-repetition exercises develop fast-twitch Type II fibers, training programs must be designed specifically according to the desired outcome.

A Decrease in Soleus Muscle Force Generation in Rats After Downhill Running

2001 ◽  
Vol 26 (4) ◽  
pp. 323-335 ◽  
Author(s):  
Antonios Kyparos ◽  
Chrysoula Matziari ◽  
Maria Albani ◽  
Georgios Arsos ◽  
Sofia Sotiriadou ◽  
...  
Keyword(s):  
Soleus Muscle ◽  
Muscle Injury ◽  
Low Frequency ◽  
Eccentric Contraction ◽  
Contractile Properties ◽  
Tetanic Force ◽  
Time To Peak ◽  
Downhill Running ◽  
Male Wistar Rats ◽  
Isometric Twitch

The purpose of the present study was to investigate the immediate and 48-hr post-exercise effects of eccentric contraction-biased exercise on the contractile properties of the soleus muscle in situ. Adult male Wistar rats were categorised into sedentary control rats (n = 10), rats studied immediately (n = 10), and rats studied 48 hours after the exercise (n = 10). The exercise protocol consisted of a 90-min intermittent downhill running (-16°, 16 m/min) on a motor-driven treadmill. The contractile properties of the soleus muscle were recorded following i.p. chloral hydrate anaesthesia. Isometric twitch force (Pt), time-to-peak tension (TPT), half-relaxation time (1/2 RT), and tetanic force at stimulation frequencies of 40, 80, and 100 Hz were recorded. A low-frequency muscle fatigue protocol (stimulation at 4 Hz for 5 min) was applied to test for fatigability. The main findings indicated that Pt generation dropped both immediately and 48 hr after the exercise, while tetanic force was partially restored after 48 hr. Exercise-induced E-C coupling failure and contractile machinery disorganisation due to muscle injury are put forward as the main force reduction causes. Key words: eccentric exercise, muscle injury, SR, E-C coupling, tension recording

Contractile properties of cat skeletal muscle after repetitive stimulation

1988 ◽  
Vol 64 (2) ◽  
pp. 502-510 ◽  
Author(s):  
D. D. Hatcher ◽  
A. R. Luff
Keyword(s):  
Recovery Period ◽  
Isometric Tension ◽  
Maximum Speed ◽  
Time To Peak ◽  
Force Velocity ◽  
Cross Bridges ◽  
Isometric Twitch ◽  
Flexor Digitorum ◽  
Fast Twitch ◽  
Speed Of Shortening

The isometric and force-velocity properties of the fast-twitch flexor digitorum longus (FDL) and slow-twitch soleus muscles were investigated immediately after and during recovery from a fatiguing stimulus regime (40 Hz for 330 ms every second for 180 s) in the anesthetized cat. The amplitude of the isometric twitch of FDL was unaffected but in soleus it remained depressed for much of the recovery period. Immediately after stimulation the twitch time to peak of FDL increased to 140% of the control (prefatigue) value and then reverted to control values. The maximum isometric tetanic tension (Po) developed by FDL was reduced to 67% of control values immediately after the stimulus regime, whereas soleus declined to 93% of control. Recovery of maximum force development was achieved after 45 min in FDL and after 15 min in soleus. The maximum speed of shortening of FDL was reduced to 63% of control values immediately after fatigue; despite some recovery within the first 30 min, it remained depressed during the remainder of the recovery period (up to 300 min). Maximum speed of shortening was unaltered in soleus. The a/Po value transiently increased to 176% of control values in FDL immediately after the fatigue regime but promptly returned to control values. Force-velocity properties of soleus were not affected by the stimulus regime. It is concluded that in FDL changes in the maximum speed of shortening and maximum isometric tension as a result of the stimulus regime are attributable to changes in the intrinsic behavior of cross-bridges and the metabolic status of the fibers, particularly in the fast-twitch fatigue-resistant fibers.

Reliability of Measuring Voluntary Strength and Isometric Twitch Properties in the Ankle Muscles of Very Old Adults

1998 ◽  
Vol 6 (3) ◽  
pp. 222-231 ◽  
Author(s):  
Karen J. Winegard ◽  
Audrey L. Hicks ◽  
Anthony A. Vandervoort
Keyword(s):  
Relaxation Time ◽  
Intraclass Correlation ◽  
Peak Torque ◽  
Very Old ◽  
Old Adults ◽  
Time To Peak ◽  
Ankle Muscle ◽  
Muscle Groups ◽  
Isometric Twitch ◽  
Voluntary Strength

The purpose of this study was to assess the reliability of measuring voluntary isometric strength, evoked isometric twitch properties (peak torque, time to peak torque, half-relaxation time), M-wave amplitude, and passive tension in very old adults (73-92 years). Five male and 5 female subjects were tested on two different test occasions that were 1 week apart. Using the intraclass correlation coefficient (ICC) method, the mean reliability coefficient of all measurements on the dorsiflexor (DF) and plantar flexor (PF) muscle groups was .91 ± .05. Similar ICC values were found for DF and PF muscles (.92 ± .04 and .90 ± .05, respectively). Resting PF half-relaxation time was the least reliable measure, with an ICC value of .80, while maximum voluntary strength was the most reliable with ICC values of .98 for DF and .97 for PF. The variation ranged from 0.2 to 12.3%. It was concluded that ankle muscle function (both voluntary and evoked) can be reliably assessed in this very old age group.

Contractile, biochemical, and histochemical properties of thyrotoxic rat soleus muscle

1980 ◽  
Vol 238 (1) ◽  
pp. C15-C20 ◽  
Author(s):  
R. H. Fitts ◽  
W. W. Winder ◽  
M. H. Brooke ◽  
K. K. Kaiser ◽  
J. O. Holloszy
Keyword(s):  
Relaxation Time ◽  
Sarcoplasmic Reticulum ◽  
Soleus Muscle ◽  
Biochemical Properties ◽  
Contractile Properties ◽  
Contraction Time ◽  
Shortening Velocity ◽  
Actomyosin Atpase ◽  
Atpase Reaction ◽  
Isometric Twitch

The effects of thyrotoxicosis on the contractile properties of soleus muscle were examined in rats given 3 mg of T4 and 1 mg of T3 per kg of diet for 6–8 wk. Thyrotoxicosis induced significant decreases in isometric twitch contraction time (CT), one-half relaxation time, and peak twitch tension. The Ca2+ uptake activity of the sarcoplasmic reticulum (SR) was increased in the thyrotoxic muscles; this adaptation in the SR provides a possible mechanism for the alterations in isometric contractile properties. Thyrotoxicosis induced a large increase in fibers classified as type 2, on the basis of an alkali-stable histochemical reaction for ATPase, in the soleus. Although this reaction is commonly interpreted as indicating that a muscle is fast, maximum shortening velocity (Vmax) and Mg2+ activated actomyosin ATPase activity were unaffected in the thyrotoxic soleus. Our findings provide evidence that CT and Vmax can vary independently and that the histochemical ATPase reaction may not always reflect the biochemical properties that make myosin fast or slow. actomyosin ATPase; histochemical ATPase reaction; isometric contraction time; maximum shortening velocity; one-half relaxation time; sarcoplasmic reticulum; skeletal muscle Submitted on April 13, 1979 Accepted on August 7, 1979

Cyclopiazonic acid-induced changes in the contraction and Ca2+ transient of frog fast-twitch skeletal muscle

1998 ◽  
Vol 274 (1) ◽  
pp. C253-C261 ◽  
Author(s):  
William Même ◽  
Corinne Huchet-Cadiou ◽  
Claude Léoty
Keyword(s):  
Skeletal Muscle ◽  
Time Constant ◽  
Force Production ◽  
Cyclopiazonic Acid ◽  
Semitendinosus Muscle ◽  
Intact Cells ◽  
Time To Peak ◽  
Intracellular Ca ◽  
Isometric Twitch ◽  
Induced Changes

The effects of cyclopiazonic acid (CPA) were investigated on isolated skeletal muscle fibers of frog semitendinosus muscle. CPA (0.5–10 μM) enhanced isometric twitch but produced little change in resting tension. At higher concentrations (10–50 μM), CPA depressed twitch and induced sustained contracture without affecting resting and action potentials. In Triton-skinned fibers, CPA had no significant effect on myofibrillar Ca2+ sensitivity but decreased maximal activated force at concentrations >5 μM. In intact cells loaded with the Ca2+fluorescence indicator indo 1, CPA (2 μM) induced an increase in Ca2+-transient amplitude (10 ± 2.5%), which was associated with an increase in time to peak and in the time constant of decay. Consequently, peak force was increased by 35 ± 4%, and both time to peak and the time constant of relaxation were prolonged. It is concluded that CPA effects, at a concentration of up to 2 μM, were associated with specific inhibition of sarcoplasmic reticulum Ca2+-adenosinetriphosphatase in intact skeletal muscle and that inhibition of the pump directly affected the handling of intracellular Ca2+ and force production.

Isometric contractile properties and velocity of shortening during avian myogenesis

1982 ◽  
Vol 243 (3) ◽  
pp. C177-C183 ◽  
Author(s):  
P. J. Reiser ◽  
B. T. Stokes ◽  
J. A. Rall
Keyword(s):  
Atpase Activity ◽  
Myosin Atpase ◽  
Contractile Properties ◽  
In Ovo ◽  
Tetanic Force ◽  
Time To Peak ◽  
Myosin Atpase Activity ◽  
Velocity Of Shortening ◽  
Isometric Twitch ◽  
Force Time

Isometric twitch and tetanic contractile properties and velocity of unloaded shortening (V0) of whole avian posterior latissimus dorsi muscle (PLD) were examined between embryonic day 15 and the first 2 wk after hatching. The time to peak twitch force, time to half-relaxation of the twitch response, and time to half-peak tetanic force all change significantly during the final week in ovo but do not change during the first 2 wk ex ovo. Comparisons with previously published reports by others indicate that the twitch half-relaxation time at hatching is approximately the same as that of the adult PLD. The velocity of unloaded shortening increases 2.3-fold during the period studied. It has previously been shown by other that the velocity of shortening is well correlated with a muscle's myosin ATPase activity. Therefore, the observed changes in V0 suggest that the myosin ATPase activity of the avian PLD increases between embryonic day 15 and the first 2 wk posthatching, and this change could account, at least in part, for some of the changes in the isometric properties that were measured.

scholarly journals Altered inotropic response to IGF-I in diabetic rat heart: influence of intracellular Ca2+and NO

1998 ◽  
Vol 275 (3) ◽  
pp. H823-H830 ◽  
Author(s):  
Jun Ren ◽  
Mary F. Walsh ◽  
Marwan Hamaty ◽  
James R. Sowers ◽  
Ricardo A. Brown
Keyword(s):  
Methyl Ester ◽  
Left Ventricular ◽  
Contractile Properties ◽  
Inotropic Response ◽  
Tension Development ◽  
Time To Peak ◽  
Igf I ◽  
Intracellular Ca ◽  
Dose Dependent Increase ◽  
Dose Dependent

Normally, insulin-like growth factor I (IGF-I) exerts positive effects on cardiac growth and myocardial contractility, but resistance to its action has been reported in diabetes. This study was designed to determine whether IGF-I-induced myocardial contractile action is altered in diabetes as a result of an intrinsic alteration of contractile properties at the cellular level. Contractile responses to IGF-I were examined in left ventricular papillary muscles and ventricular myocytes from normal and short-term (5–7 days) streptozotocin-induced diabetic rats. Mechanical properties of muscles and myocytes were evaluated using a force transducer and an edge detector, respectively. Preparations were electrically stimulated at 0.5 Hz, and contractile properties analyzed include peak tension development (PTD) or peak twitch amplitude (PTA), time to peak contraction/shortening, and time to 90% relaxation/relengthening. Intracellular Ca2+ transients were measured as fura 2 fluorescence intensity changes. IGF-I (1–500 ng/ml) caused a dose-dependent increase in PTD and PTA in preparations from normal but not diabetic animals. IGF-I did not alter time to peak contraction/shortening or time to 90% relaxation/relengthening. Pretreatment with the NO synthase inhibitor N ω-nitro-l-arginine methyl ester (100 μM) attenuated IGF-I-induced increases in PTD in normal myocardium but unmasked a positive inotropic action in diabetic animals. Pretreatment with N ω-nitro-l-arginine methyl ester blocked IGF-I-induced increases in PTA in single myocytes. Consistent with its inotropic actions on muscles and myocytes, IGF-I induced a dose-dependent increase in Ca2+transients in normal but not diabetic myocytes. These results suggest that the IGF-I-induced inotropic response is depressed in diabetes because of an intrinsic alteration at the myocyte level. Mechanisms underlying this alteration in IGF-I-induced myocardial response may be related to changes in intracellular Ca2+ and/or NO production in diabetes.

Bufadienolides from the Eggs of the Toad Bufo bufo gargarizans and Their Antimelanoma Activities

2021 ◽  
Author(s):  
Shi-wen Zhou ◽  
Jing-yu Quan ◽  
Zi-wei Li ◽  
Ge Ye ◽  
Zhuo Shang ◽  
...  
Keyword(s):  
Bufo Bufo ◽  
Bufo Gargarizans ◽  
Toad Bufo ◽  
Toad Bufo Bufo
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