scholarly journals Physical and biochemical energy balance during an isometric tetanus and steady state recovery in frog sartorius at 0 degree C.

1983 ◽  
Vol 81 (3) ◽  
pp. 337-354 ◽  
Author(s):  
R J Paul
Keyword(s):  
Steady State ◽  
Heat Production ◽  
Isometric Force ◽  
Recovery Period ◽  
Lactate Production ◽  
High Energy ◽  
Sartorius Muscle ◽  
State Recovery ◽  
Frog Sartorius ◽  
Initial Heat

Frog sartorius muscle stimulated isometrically for 3 s every 256 s to attain a steady state in which initial heat (QI), recovery heat (QR), rate of O2 consumption (JO2), and isometric force (PO) generated are constant for each cycle. For a 3-s tetanus given every 256 s, JO2 was 0.106 mumol/(min . g blotted weight), approximately 71% of the maximum rate observed, whereas lactate production was negligible under these conditions. QI, QT(= QI + QR), and QT/QI were 88.2, 181.5, 2.06 mJ/g blotted weight, respectively. The high-energy phosphate breakdown (delta approximately P) breakdown during the first 3-s tetanus was not different from that during a contraction in the steady state and averaged 1.1 mumol/g blotted weight. Less than half of the initial heat could be accounted for in terms of the extent of the known chemical reactions occurring during contraction. From the stoichiometry of the theoretical biochemical pathways, the amount of ATP synthesized in the steady state exceeds delta approximately P during contraction by more than twofold, corresponding to an apparent ADP:O ratio of 1.5. If it is assumed that carbohydrate oxidation is the only net chemical reaction in the steady state, the total heat production can be explained on the basis of the measured JO2. Under this assumption, heat production during recovery was less than that expected on the basis of the oxygen consumption and delta approximately P during contraction. These observations support the hypothesis that the unexplained enthalpy production and low apparent ADP:O ratio are causally related, i.e., that the reaction(s) producing the unexplained heat during contraction is reversed during the recovery period.

scholarly journals Initial Heat Production in Isometric Frog Muscle at 15°C

1973 ◽  
Vol 62 (3) ◽  
pp. 271-285 ◽  
Author(s):  
Allan Fraser ◽  
Francis D. Carlson
Keyword(s):  
Heat Production ◽  
Sarcomere Length ◽  
Heat Rate ◽  
Frog Muscle ◽  
Mechanical Activity ◽  
Sartorius Muscle ◽  
Cooling Phase ◽  
Frog Sartorius ◽  
Initial Heat ◽  
Rest Length

An infrared radiation-detecting system was used to measure initial heat production in bull frog sartorius muscle at 15°C. Numerous tests with the system showed that thermal artifacts were not noticeable. Many previous measurements with myothermic thermopiles were corroborated with this method. In addition, a cooling phase as large as 0.39 of peak exothermicity was found during and after relaxation. Cooling diminished with both increasing sarcomere length and increasing duration of mechanical activity. No large rapid increase in heat rate accompanied a 0.6 reactivation at the peak of twitch tension. Above rest length, initial heat rate and the heat produced up to the peak of tension decreased nearly proportionally with overlap of myofilaments, while the total twitch initial heat decreased slightly.

Transient changes in muscle high-energy phosphates during moderate exercise

1993 ◽  
Vol 75 (2) ◽  
pp. 648-656 ◽  
Author(s):  
G. D. Marsh ◽  
D. H. Paterson ◽  
J. J. Potwarka ◽  
R. T. Thompson
Keyword(s):  
Oxygen Consumption ◽  
Steady State ◽  
Recovery Period ◽  
High Energy ◽  
Second Order ◽  
Moderate Intensity ◽  
High Energy Phosphates ◽  
Order Model ◽  
Time Constants ◽  
First Order

The purpose of this study was to use 31P-nuclear magnetic resonance spectroscopy to examine changes in wrist flexor muscle metabolism during the transitions from rest to steady-state exercise (on-transient) and back to rest (off-transient). Five healthy young males (mean age 25 +/- 2 yr) performed a series of square-wave exercise tests, each consisting of 5 min of moderate-intensity work followed by a 5-min recovery period. The subjects repeated this protocol six times, and each individual's results were pooled before analysis. ATP and intracellular pH did not change significantly during exercise or recovery. Phosphocreatine (PCr) declined progressively at the onset of exercise, reaching a plateau after approximately 2 min. A reciprocal increase in Pi occurred during the onset of exercise. During the recovery period PCr was resynthesized, whereas Pi returned to resting levels. The data were plotted as a function of time and fit with both first- and second-order exponential growth or decay models; however, the second-order model did not significantly improve the fit of the data. Time constants for the first-order model of the on- and off-transient responses for both PCr and Pi were approximately 30 s. These values are nearly identical to the time constants for oxygen consumption during submaximal exercise that have been reported previously by several authors. The results of this study show that the metabolism of muscle PCr during steady-state exercise and recovery can be accurately described by a monoexponential model and, further, suggest that a first-order proportionality exists between metabolic substrate utilization and oxygen consumption.

scholarly journals Energy balance studies in frog skeletal muscles shortening at one-half maximal velocity.

1984 ◽  
Vol 84 (3) ◽  
pp. 347-359 ◽  
Author(s):  
E Homsher ◽  
T Yamada ◽  
A Wallner ◽  
J Tsai
Keyword(s):  
Skeletal Muscles ◽  
Maximum Velocity ◽  
High Energy ◽  
Sartorius Muscle ◽  
Maximal Velocity ◽  
High Energy Phosphate ◽  
The Mean ◽  
S Period ◽  
High Energy Phosphate Metabolism ◽  
Frog Sartorius

High-energy phosphate metabolism and energy liberated as heat and work were measured in 3-s tetani of frog sartorius muscle at 0 degree C. Two contraction periods were studied: (a) a 0.35-s period of shortening near half-maximum velocity beginning after 2 s of isometric stimulation, and (b) a 0.65-s isometric period immediately following the shortening. There were no significant changes in levels of ATP, ADP, or AMP in the two contraction periods. The observed changes in inorganic phosphate and creatine levels indicated that the only significant reaction occurring was phosphocreatine splitting. The mean rate of high-energy phosphate splitting during the shortening, 1.60 +/- 0.23 mumol X g-1 X s-1 (n = 24), was about fivefold higher than that in the 1-s period in the isometric tetanus, 0.32 +/- 0.11 mumol X g-1 X s-1 (n = 17), observed in our previous study. The mean rate in the post-shortening period, 0.46 +/- 0.13 mumol X g-1 X s-1 (n = 17), was not significantly different from that in the 1-s period in the isometric tetanus. A large amount of heat plus work was produced during the shortening period, and this could be accounted for by simultaneous chemical changes. In the post-shortening period, the observed enthalpy was also accounted for by simultaneous chemical reactions. Thus, the present result is in sharp contrast to that obtained from a similar study performed at a shortening at Vmax, where an enthalpy excess was produced during shortening and an enthalpy deficit was produced during the period following the shortening.

Seasonal variation in muscle fatigue in the sartorius muscle of the frog Rana pipiens

1991 ◽  
Vol 69 (6) ◽  
pp. 1712-1715
Author(s):  
Jean Marc Renaud
Keyword(s):  
Seasonal Variation ◽  
Rana Pipiens ◽  
Recovery Period ◽  
Sartorius Muscle ◽  
Tetanic Force ◽  
Fatigue Development ◽  
Significant Seasonal Variation ◽  
Significant Difference ◽  
Force Recovery ◽  
Frog Sartorius

The goal of this study was to determine whether seasonal variation occurs in the rates of fatigue development and force recovery in the frog sartorius muscle. The data were gathered from different experiments performed during a 6-year period (1983–1989). All frog sartorius muscles were stimulated to fatigue with tetanic contractions at the rate of 1/s for 3 min. The decrease in tetanic force after 1.5 and 3 min of stimulation was relatively consistent throughout the year. The only significant difference occurred in the muscles tested in September and October, which were less fatigue resistant than those tested in December. Following fatigue, muscles were stimulated at the rate of one contraction every 100 s, so that the recovery of tetanic force could be followed. A large and significant seasonal variation was observed in the recovery period. Frog sartorius muscles tested between March and July recovered their tetanic force at a faster rate than those tested between August and October. It was shown that the highest capacity to recover force coincides with the time of the year when frogs are the most active.

scholarly journals Chemical energetics of slow- and fast-twitch muscles of the mouse.

1982 ◽  
Vol 79 (1) ◽  
pp. 147-166 ◽  
Author(s):  
M T Crow ◽  
M J Kushmerick
Keyword(s):  
Energy Cost ◽  
Recovery Period ◽  
Chemical Change ◽  
Lactate Production ◽  
High Energy ◽  
Isometric Tension ◽  
Energy Utilization ◽  
Slow Twitch ◽  
The Cost ◽  
Fast Twitch

The energy utilization associated with contraction was measured in isolated slow- and fast-twitch muscles of the mouse at 20 degrees C. The extent of this utilization was estimated from either the extent of high-energy phosphate splitting occurring during contraction (the initial chemical change, delta approximately P init) or from the extent of recovery resynthesis calculated from the observed oxygen consumption and lactate production occurring during the recovery period (recovery chemical resynthesis, delta approximately P rec). For short tetani, the cost to maintain isometric tension in the fast-twitch extensor digitorum longus (EDL) was approximately threefold greater than that in the slow-twitch soleus. With prolonged stimulation, however, the energy cost in the EDL diminished so that after 12 s of stimulation, the energy cost in the EDL was only 50% greater than that of the soleus. For both the slow-twitch soleus and the fast-twitch EDL and for all tetanus durations (up to 15 s), the extent of the initial chemical change was identical with the amount of recovery chemical resynthesis, showing that a biochemical energy balance existed in these muscles.

scholarly journals The relation between initial and recovery heat production in frog's nerve

1933 ◽  
Vol 113 (784) ◽  
pp. 369-386 ◽  
Keyword(s):  
Steady State ◽  
Heat Production ◽  
Short Interval ◽  
Preceding Paper ◽  
Heat Rate ◽  
Recovery Process ◽  
Quantitative Relation ◽  
Rate Of Recovery ◽  
Initial Heat

The latest and best determination of the quantitative relation of the two chief phases of heat production in frog's nerve is that of Bronk (1931) who found the average ratio of total to initial heat to be 11. More recently Hill (1932) has given reason to believe that even Bronk's ratio is probably too low, and in the same paper (p. 148) has suggested an alternative method of estimating it based on the principle of the steady state. the present work arose from this suggestion and has led to the discovery of the profound effect of steady activity on the “efficiency” of the recovery process. The steady state of nerve activity during continual stimulation has been discussed in a preceding paper. Its nature is such that the rate of recovery heat production at any moment corresponds to the rate of initial heat production at that moment. the total heat rate can easily be measured. The initial heat rate can be determined by omitting the stimulus for a short interval, when an analysis of the resulting defection allows an estimate of the heat which immediately drops out as a result of omitting the stimulus, i. e ., of the initial heat.

scholarly journals Recovery heat in muscle

1939 ◽  
Vol 127 (848) ◽  
pp. 297-307 ◽  
Keyword(s):  
Steady State ◽  
Heat Production ◽  
Resting Metabolic Rate ◽  
Heat Rate ◽  
Base Line ◽  
Large Increment ◽  
Prolonged Heat ◽  
Resting Muscle ◽  
Initial Heat ◽  
Half Minute

It has been suggested (Sacks 1938, p. 222) “that the post-stimulation heat (in muscle) merely represents the inertia of the tissue in returning to the resting metabolic level after a burst activity.” It is true that the recovery heat after a single contraction , as ordinary observed, would not mean a very large increment in the resting metabolic rate, and that for single contractions it can be accurately measured only by assuming the resting heat rate as a constant base-line. Single contractions, however, have not provided the only, or indeed the strongest, evidence for the existence of the recovery heat; for example: (i) Hill (1928 a , p. 188) showed that if oxygen is admitted to a muscle previously stimulated in nitrogen a large and prolonged heat production occurs: this experiment is regularly given as a class demonstration in this laboratory; (ii) Hill (1928 a , p. 185) showed that during and after a long regular series of twiches the heat production in oxygen is considerably, not slighlty, greater than it is nitrogen; (iii) Bugnard (1934) examined the relation between total heat and initial heat during the steady state due to a regular series of shocks in oxygen. The recovery heat, as usual, was about equal to the initial heat. Its accumulated rate, however, was high, not low as after a single contraction. An amount of recovery heat equal to the initial heat occurred every half minute (the interval between shocks) throughtout the steady state. The heat rate during the interval between two shocks was about three times that of the resting muscle.

Transient and Steady-State Force Enhancement in the Drosophila Jump Muscle

2012 ◽  
Author(s):  
Ryan A. Koppes ◽  
Douglas M. Swank ◽  
David T. Corr
Keyword(s):  
Steady State ◽  
Isometric Force ◽  
Recovery Period ◽  
Underlying Mechanism ◽  
Clear Correlation ◽  
Force Enhancement ◽  
Force Depression ◽  
Force Recovery ◽  
State Force ◽  
Whole Muscle

The increase of isometric force after active lengthening, termed force enhancement (FE), is a well-accepted characteristic of skeletal muscle that has been demonstrated in both whole muscle [1,3] and single-fiber preparations [1,2]. The amount of FE increases with increasing amplitudes of stretch, yet no clear correlation between FE and the rate stretch has been demonstrated [2]. Although this behavior has been observed experimentally for over 70 years, its underlying mechanism(s) remain unknown. Furthermore, most studies of FE have been limited to steady-state (FESS) observations [1–3], whereas clues to the underlying mechanism(s) may very well exist in the transient force recovery period following an active stretch, as seen in another history-dependent phenomenon, force depression [4].

Equatorial X-ray intensities and isometric force levels in frog sartorius muscle

1979 ◽  
Vol 132 (1) ◽  
pp. 53-67 ◽  
Author(s):  
Leepo C. Yu ◽  
Jacqueline E. Hartt ◽  
Richard J. Podolsky
Keyword(s):  
Isometric Force ◽  
Sartorius Muscle ◽  
X Ray ◽  
Frog Sartorius Muscle ◽  
Frog Sartorius

Energetics of isometric contractions as a function of muscle temperature

1983 ◽  
Vol 244 (1) ◽  
pp. C100-C109 ◽  
Author(s):  
L. C. Rome ◽  
M. J. Kushmerick
Keyword(s):  
Isometric Force ◽  
Regression Line ◽  
Lactate Production ◽  
High Energy ◽  
Regression Equation ◽  
Energetic Cost ◽  
Regression Equations ◽  
Total Recovery ◽  
Start Up ◽  
The Cost

The energetic cost of generating isometric force in isolated frog muscle was examined at 10, 20, and 30 degrees C. Recovery O2 consumption (delta O2) and recovery lactate production (delta Lact) were measured under conditions in which O2 was not limiting metabolism. Both increased linearly with the force-time integral (integral of Fdt) generated by the muscle. The slopes of the regression equations for both delta O2 and delta Lact as a function of integral of Fdt increased with increasing temperature with a temperature coefficient (Q10) near 3. Total high-energy phosphate resynthesis from recovery metabolism was calculated by scaling the delta O2 regression equation and the delta Lact regression equation into equivalent ATP units and summing them. This total recovery metabolism was modeled as the sum of two components, a "cost of maintaining force" (slope of the equation) and a saturable "start up cost" (intercept of the equation). The cost of maintaining force increased with temperature with a Q10 near 3 over the whole temperature range, whereas the start up cost was nearly independent of temperature between 0 and 20 degrees C and fell to near zero at 30 degrees C. Delta O2 measurements from a series of tetani given in rapid succession showed that for contractions subsequent to the first, no start up cost was incurred and that the "cost of generating force" for these contractions was equal to the slope of the regression line for single tetani. The practical consequence of these facts is that, in series of tetani, the cost of generating force increases with a Q10 of 3.

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