Lactate and contractile force in frog muscle during development of fatigue and recovery

1976 ◽  
Vol 231 (2) ◽  
pp. 430-433 ◽  
Author(s):  
RH Fitts ◽  
JO Holloszy
Keyword(s):  
Lactate Concentration ◽  
Contractile Force ◽  
Sartorius Muscle ◽  
Second Phase ◽  
Initial Value ◽  
Muscle Lactate ◽  
Total Recovery ◽  
Two Phases ◽  
The Relationship ◽  
Frog Sartorius

The relationship between lactic acid concentration and twitch tension was reevaluated in electrically stimulated frog sartorius muscle. In muscles stimulated under anaerobic conditions at a rate of 30 stimuli/MIN CONTRACTILE FORCE DECREASED TO 36% OF THE INITIAL VALUE IN 15 MIN, Concomitantly lactate increased from 3.3 to 18.7 mumol/g of muscle. The correlaiton between the increase in lactate and the decrease in contractile force was significant (r = -0.99, P less than 0.000001). Recovery occurred in two phases. A rapid increase in contractile force, which represented 20% of the total recovery, took place during the first 15 s and occurred concomitantly with an increase in ATP from 3.9 to 4.6 mumol/g. Lactate concentration did not change significantly during this period. The second phase of recovery of contractile force was complete in 50 min. Lactate concentration and contractile force were significatly correlated during recovery (r = -0;92, P less than 0.00001). However, recovery of contractile force lagged behind the decrease in lactate; a given concentration of muscle lactate was associated with a higher contractile force early during development of fatigue than late during recovery.

Effects of extracellular pH on lactate efflux from frog sartorius muscle

1984 ◽  
Vol 247 (3) ◽  
pp. C175-C181 ◽  
Author(s):  
Y. Seo
Keyword(s):  
Lactate Concentration ◽  
Extracellular Ph ◽  
Sartorius Muscle ◽  
Mechanism Analysis ◽  
Ph Change ◽  
Concentration Difference ◽  
1H Nuclear Magnetic Resonance ◽  
Efflux Mechanism ◽  
The Relationship ◽  
Frog Sartorius

The isolated sartorius muscle of frog was stimulated under an anaerobic condition, and intracellular lactate concentration and intracellular pH was determined sequentially by 1H-nuclear magnetic resonance, and the efflux of lactate was measured by an enzymatic method on the incubation media with different pH levels. The lactate efflux was shown to increase in proportion to the concentration difference of lactate across the membrane up to 25 mmol X l H2O-1, and the permeability of the membrane to lactate increased with the increment of extracellular pH. H+ efflux was determined from pH change and the buffer capacity of incubation medium. The efflux of H+ rose approximately linearly with the efflux of lactate up to approximately 70 mumol X min-1 X l H2O-1, and the relationship then revealed a clear leveling off. From these results the efflux of lactate was analyzed in terms of a predominantly nonionic or a predominantly ionic efflux mechanism. Analysis showed that the mechanism of efflux was in both the ionic and nonionic form.

scholarly journals The Relationship Between English Language Proficiency and Politeness in Making Requests: A Case Study of ESL Saudi Students

2019 ◽  
Vol 9 (2) ◽  
pp. 89
Author(s):  
Abdullah Alshakhi
Keyword(s):  
Language Proficiency ◽  
English Language ◽  
English Proficiency ◽  
The United States ◽  
English Language Proficiency ◽  
Language Learner ◽  
Second Phase ◽  
Saudi Students ◽  
Two Phases ◽  
The Relationship

The acquisition of language as well as the acquisition of social consideration, or politeness, are two sets of separate skills. However, the lack of language knowledge by an English language learner can result in social mistakes that can be perceived as impolite by native speakers. The present study aimed to explore the relationship between English language proficiency and politeness in making requests at retail shops, specifically focusing on Saudi students in the United States. There were five participants in this study: two Saudi ESL students with low English proficiency; two Saudi Ph. D. students with advanced English proficiency, and an American waiter who speaks English as a native language. The study was conducted by using a qualitative research method in two phases. The first phase included observing all participants during interaction, and the second phase included interviewing a server at one of the restaurants where the students visited. The main findings revealed that there was no strong correlation between politeness and English language proficiency in making requests. However, there were some factors found in this study that contributed to politeness level, such as intonations and the use of politeness markers.

scholarly journals Two S. pombe septation phases differ in ingression rate, septum structure, and response to F-actin loss

2019 ◽  
Vol 218 (12) ◽  
pp. 4171-4194 ◽  
Author(s):  
Mariona Ramos ◽  
Juan Carlos G. Cortés ◽  
Mamiko Sato ◽  
Sergio A. Rincón ◽  
M. Belén Moreno ◽  
...  
Keyword(s):  
Fission Yeast ◽  
Dual Function ◽  
Second Phase ◽  
Glucan Synthase ◽  
Two Phases ◽  
Anaphase B ◽  
The Relationship ◽  
Contractile Structure ◽  
In Cells

In fission yeast, cytokinesis requires a contractile actomyosin ring (CR) coupled to membrane and septum ingression. Septation proceeds in two phases. In anaphase B, the septum ingresses slowly. During telophase, the ingression rate increases, and the CR becomes dispensable. Here, we explore the relationship between the CR and septation by analyzing septum ultrastructure, ingression, and septation proteins in cells lacking F-actin. We show that the two phases of septation correlate with septum maturation and the response of cells to F-actin removal. During the first phase, the septum is immature and, following F-actin removal, rapidly loses the Bgs1 glucan synthase from the membrane edge and fails to ingress. During the second phase, the rapidly ingressing mature septum can maintain a Bgs1 ring and septum ingression without F-actin, but ingression becomes Cdc42 and exocyst dependent. Our results provide new insights into fungal cytokinesis and reveal the dual function of CR as an essential landmark for the concentration of Bgs1 and a contractile structure that maintains septum shape and synthesis.

scholarly journals Local movement in stimulated frog sartorius muscle.

1981 ◽  
Vol 78 (2) ◽  
pp. 151-170 ◽  
Author(s):  
G J Stienen ◽  
T Blangé
Keyword(s):  
Relative Length ◽  
Length Change ◽  
Sartorius Muscle ◽  
Tension Development ◽  
Frog Sartorius Muscle ◽  
Local Movement ◽  
Length Changes ◽  
Two Phases ◽  
Frog Sartorius ◽  
Relative Length Change

Local movement was recorded in tetanically contracting frog sartorius muscle to estimate the nonuniformity in the distribution of compliance in the muscle preparation and the compliance that resides in the attachments of the preparation to the measuring apparatus. The stimulated muscle was also subjected to rapid length changes, and the local movements and tension responses were recorded. The results indicate that during tension development at resting length the central region of the muscle shortens at the expense of the ends. After stimulation the "shoulder" in the tension, which divided the relaxation into a slow decline and a subsequent, rather exponential decay toward zero, was accompanied by an abrupt increase in local movement. We also examined the temperature sensitivity of the two phases of relaxation. The results are consistent with the view that the decrease in tension during relaxation depends on mechanical conditions. The local movement brought about by the imposed length changes indicates that the peak value of the relative length change of the uniformly acting part was approximately 20% less than the relative length change of the whole preparation. From these observations, corrections were obtained for the compliance data derived from the tension responses. These corrections allow a comparison with data in the literature obtained from single fiber preparations. The implications for the stiffness measured during the tension responses are discussed.

Qualitative measurements of the entry of L-lactate into single surface fibres of frog skeletal muscle using a lactate-sensitive microelectrode

1987 ◽  
Vol 65 (12) ◽  
pp. 2488-2491 ◽  
Author(s):  
M. J. Mason
Keyword(s):  
Skeletal Muscle ◽  
Lactate Concentration ◽  
Ion Exchanger ◽  
Sartorius Muscle ◽  
Muscle Fibres ◽  
Frog Skeletal Muscle ◽  
Frog Sartorius Muscle ◽  
Frog Sartorius ◽  
Qualitative Measurements ◽  
Liquid Ion Exchanger

The present results demonstrate the sensitivity of the Corning chloride liquid ion exchanger 477913 to L-lactate. Microelectrodes filled with this exchanger showed responses to changes in L-lactate concentration in chloride-free solutions. In these experiments L-lactate replaced gluconate in equimolar amounts. Microelectrodes filled with this exchanger were used to qualitatively detect changes in intracellular anion in chloride-depleted frog sartorius muscle fibres during exposure to extracellular concentrations of L-lactate. The increase in intracellular anion concentration is consistent with the movement of L-lactate into the cell. This microelectrode enables one to qualitatively monitor changes in intracellular L-lactate in chloride-free experiments without incorporating selectivity coefficients.

scholarly journals Cross-Modal Perceptual Organization in Works of Art

i-Perception ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 204166952095075
Author(s):  
Liliana Albertazzi ◽  
Luisa Canal ◽  
Rocco Micciolo ◽  
Iacopo Hachen
Keyword(s):  
Semantic Differential ◽  
Second Phase ◽  
Abstract Concepts ◽  
Piano Works ◽  
Musical Excerpts ◽  
Bipolar Scale ◽  
Two Phases ◽  
Perceptual Characteristics ◽  
The Relationship ◽  
Differential Test

This study investigates the existence of cross-modal correspondences between a series of paintings by Kandinsky and a series of selections from Schönberg music. The experiment was conducted in two phases. In the first phase, by means of the Osgood semantic differential, the participants evaluated the perceptual characteristics first of visual stimuli (some pictures of Kandinsky’s paintings, with varying perceptual characteristics and contents) and then of auditory stimuli (musical excerpts taken from the repertoire of Schönberg’s piano works) relative to 11 pairs of adjectives tested on a continuous bipolar scale. In the second phase, participants were required to associate pictures and musical excerpts. The results of the semantic differential test show that certain paintings and musical excerpts were evaluated as semantically more similar, while others were evaluated as semantically more different. The results of the direct association between musical excerpts and paintings showed both attractions and repulsions among the stimuli. The overall results provide significant insights into the relationship between concrete and abstract concepts and into the process of perceptual grouping in cross-modal phenomena.

scholarly journals EMG activity in hyoid muscles during pig suckling

2012 ◽  
Vol 112 (9) ◽  
pp. 1512-1519 ◽  
Author(s):  
A. J. Thexton ◽  
A. W. Crompton ◽  
R. Z. German
Keyword(s):  
Emg Activity ◽  
Cycle Period ◽  
Second Phase ◽  
Cycle Duration ◽  
Fixed Duration ◽  
Cervical Plexus ◽  
Pharyngeal Swallow ◽  
Two Phases ◽  
Pharyngeal Swallowing ◽  
The Relationship

Infant suckling is a complex behavior that includes cycles of rhythmic sucking as well as intermittent swallows. This behavior has three cycle types: 1) suck cycles, when milk is obtained from the teat and moved posteriorly into the valleculae in the oropharynx; 2) suck-swallow cycles, which include both a rhythmic suck and a pharyngeal swallow, where milk is moved out of the valleculae, past the larynx, and into the esophagus; and 3) postswallow suck cycles, immediately following the suck-swallow cycles. Because muscles controlling these behaviors are active in all three types of cycles, we tested the hypothesis that different patterns of electromyographic (EMG) activity in the mylohyoid, hyoglossus, stylohyoid, and thyrohyoid muscles of the pig characterized each cycle type. Anterior mylohyoid EMG activity occurred regularly in every cycle and was used as a cycle marker. Thyrohyoid activity, indicating the pharyngeal swallow, was immediately preceded by increased stylohyoid and hyoglossus activity; it divided the suck-swallow cycle into two phases. Timed from the onset of the suck-swallow cycle, the first phase had a relatively fixed duration while the duration of the second phase, timed from the thyrohyoid, varied directly with cycle duration. In short-duration cycles, the second phase could have a zero duration so that thyrohyoid activity extended into the postswallow cycle. In such cycles, all swallowing activity that occurred after the thyrohyoid EMG and was associated with bolus passage through the pharynx fell into the postswallow cycle. These data suggest that while the activity of some muscles, innervated by trigeminal and cervical plexus nerves, may be time locked to the cycle onset in swallowing, the cycle period itself is not. The postswallow cycle consequently contains variable amounts of pharyngeal swallowing EMG activity. The results exemplify the complexity of the relationship between rhythmic sucking and the swallow.

Organ culture of frog muscle: maintenance of mass, enzyme levels, and contractile force

1989 ◽  
Vol 67 (1) ◽  
pp. 466-471 ◽  
Author(s):  
Y. Ohira ◽  
M. Ohira ◽  
M. Chen ◽  
J. O. Holloszy
Keyword(s):  
Creatine Kinase ◽  
Lactate Dehydrogenase ◽  
Organ Culture ◽  
Citrate Synthase ◽  
Good Condition ◽  
Dry Weight ◽  
Contractile Force ◽  
Sartorius Muscle ◽  
Clear Cut ◽  
Frog Sartorius

This paper describes an organ culture system that maintains frog sartorius muscles in good condition for 5 days. In the absence of serum and insulin, muscles maintained at approximately 93% of resting length atrophied with significant decreases in dry weight, protein content, and contractile force, and in the levels of activity of citrate synthase, lactate dehydrogenase, and creatine kinase. Inclusion of 1.0 mU/ml of insulin in the culture medium prevented the decreases in muscle mass, twitch tension, and citrate synthase activity and minimized the decreases in lactate dehydrogenase, creatine kinase, and tetanic tension. Inclusion of 10% serum, in addition to 1 mU/ml insulin, in the medium did not have clear cut additional benefits. Stretching muscles to 110% of resting length (L0) resulted in marked deterioration with decreases in total protein, enzyme levels, and contractile force. Keeping muscles at approximately 93% L0 was as effective as maintenance at L0 in preventing atrophy and loss of contractile force and enzyme activities. This organ culture procedure, which maintains frog sartorius muscle in good condition without serum for at least 5 days, may provide a useful model for studying the regulatory mechanisms responsible for a variety of adaptations in muscle.

Lactate release in relation to tissue lactate in human skeletal muscle during exercise

1978 ◽  
Vol 44 (3) ◽  
pp. 350-352 ◽  
Author(s):  
L. Jorfeldt ◽  
A. Juhlin-Dannfelt ◽  
J. Karlsson
Keyword(s):  
Blood Flow ◽  
Vastus Lateralis ◽  
Lactate Concentration ◽  
Work Intensity ◽  
Muscle Lactate ◽  
Lactate Release ◽  
Leg Blood Flow ◽  
Constant Rate ◽  
The Relationship ◽  
Muscle Biopsies

In four healthy volunteers, muscle lactate concentration and the release of lactate from the leg were determined at rest and at 4 and 12 min of sitting bicycle exercise at four intensities (30, 50, 70, and 90% of maximal oxygen uptake). The muscle biopsies were obtained by needle biopsy technique from m. vastus lateralis. The rate of lactate release was calculated from the femoral venous-arterial differences of lactate and the leg blood flow was determined by constant rate dye infusion. Both leg blood flow and leg oxygen consumption increased linearly with work intensity. The release of lactate rose approximately linearly with the muscle lactate concentration up to about 4–5 mmol/min but then the relationship revealed a clear leveling off. These results indicate a maximal level for the lactate release from the exercising muscles with a translocation hindrance for lactate within the muscles.

scholarly journals The Variation of Muscle Oxygen Consumption With Velocity of Shortening

1965 ◽  
Vol 49 (1) ◽  
pp. 9-15 ◽  
Author(s):  
R. J. Baskin
Keyword(s):  
Oxygen Consumption ◽  
Mechanical Efficiency ◽  
Sartorius Muscle ◽  
Maximum Oxygen Consumption ◽  
Shortening Velocity ◽  
Muscle Oxygen ◽  
Velocity Of Shortening ◽  
Muscle Oxygen Consumption ◽  
The Relationship ◽  
Frog Sartorius

Total oxygen consumption following contraction at controlled shortening velocities was determined for ten twitches of frog sartorius muscle. Under the conditions of this investigation maximum oxygen consumption occurred at approximately 30 mm/sec. shortening velocity and decreased for larger and smaller velocities. Mechanical efficiency was calculated and found to show a maximum at approximately 20 mm/sec. shortening velocity. The relationship between this study and a similar investigation in which heat changes are measured as a function of shortening velocity is discussed.

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