Training Intensity, Not Duration, May Be Key to Upregulating Presynaptic Proteins of Calcium Dynamics and Calcium-Dependent Exocytosis in Fast- and Slow-Twitch Skeletal Muscles, in Addition to Maintaining Performance After Detraining

2021 ◽  
Author(s):  
Ali Gorzi ◽  
Fatemeh Jafari ◽  
Nasrin Allahmoradi ◽  
Ahmad Rahmani ◽  
Walter Krause Neto
Keyword(s):  
Skeletal Muscles ◽  
Calcium Dynamics ◽  
Training Intensity ◽  
Calcium Dependent ◽  
Slow Twitch ◽  
Presynaptic Proteins

A SIMPLE MODEL FOR INTERACTION OF VOLTAGE AND CALCIUM DYNAMICS IN VIRTUAL VENTRICULAR TISSUE

2003 ◽  
Vol 13 (12) ◽  
pp. 3873-3886
Author(s):  
O. V. ASLANIDI ◽  
A. V. HOLDEN
Keyword(s):  
Intracellular Calcium ◽  
Calcium Release ◽  
Cell Model ◽  
Excitation Threshold ◽  
Calcium Dynamics ◽  
Variable Model ◽  
Ventricular Cell ◽  
Calcium Dependent ◽  
Intracellular Ca ◽  
A Site

A simple two-variable model is used to replace the formulation of calcium dynamics in the Luo–Rudy ventricular cell model. Virtual ventricular cell and tissue are developed and validated to reproduce restitution properties and calcium-dependent voltage patterns present in the original model. Basic interactions between the membrane potential and Ca 2+ dynamics in the virtual cell and a strand of the virtual tissue are studied. Intracellular calcium waves can be linked to both action potentials (APs) and delayed afterdepolarizations (DADs). An intracellular calcium wave propagating from the cell interior can induce an AP upon reaching the cell membrane. The voltage and the intracellular Ca 2+ patterns within the same cell can be highly desynchronized. In a one-dimensional strand of the virtual tissue calcium motion is driven by the AP propagation. However, calcium release can be induced upon certain conditions (e.g. Na + overload of the cells), which results in DADs propagating in the wake of AP. Such propagating DADs can reach the excitation threshold, generating a pair of extrasystolic APs. Collision of a propagating AP with a site of elevated intracellular Ca 2+ concentration does not affect the propagation under the normal conditions. Under Na + overload local elevation of the intracellular Ca 2+ leads to generation of an extrasystolic AP, which destroys the original propagating AP.

Increased lipoprotein lipase activity of skeletal muscle in cold-acclimated rats

1977 ◽  
Vol 55 (12) ◽  
pp. 1241-1243 ◽  
Author(s):  
N. Bégin-Heick ◽  
H. M. C. Heick
Keyword(s):  
Skeletal Muscle ◽  
Cold Acclimation ◽  
Lipoprotein Lipase ◽  
Lipase Activity ◽  
Skeletal Muscles ◽  
Lipoprotein Lipase Activity ◽  
Slow Twitch ◽  
Respiratory Movements ◽  
Parallel Fashion

The activity of lipoprotein lipase (LPL) in the heart, diaphragm, and soleus muscles was markedly increased in cold-acclimated rats and it was even greater in rats treated with oxytetracycline (OTC) while exposed to cold. Other skeletal muscles studied had low and variable activities which were not significantly increased by cold acclimation or by cold plus OTC treatment. It appears therefore that, apart from the heart and the muscles involved in respiratory movements, LPL activity is primarily associated with those muscles which contain a predominance of slow-twitch oxidative fibers, and that the enzyme in muscle, heart, and diaphragm responds to cold acclimation and cold plus OTC treatment in a parallel fashion in these tissues.

Glutamine synthetase induction by glucocorticoids is preserved in skeletal muscle of aged rats

1996 ◽  
Vol 271 (6) ◽  
pp. E1061-E1066 ◽  
Author(s):  
D. Meynial-Denis ◽  
M. Mignon ◽  
A. Miri ◽  
J. Imbert ◽  
E. Aurousseau ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Glutamine Synthetase ◽  
Skeletal Muscles ◽  
Female Rats ◽  
Mrna Levels ◽  
Aged Rats ◽  
Adult Rats ◽  
Adult Age ◽  
Slow Twitch ◽  
Fast Twitch

Glutamine synthetase (GS) is a glucocorticoid-inducible enzyme that has a key role for glutamine synthesis in muscle. We hypothesized that the glucocorticoid induction of GS could be altered in aged rats, because alterations in the responsiveness of some genes to glucocorticoids were reported in aging. We compared the glucocorticoid-induced GS in fast-twitch and slow-twitch skeletal muscles (tibialis anterior and soleus, respectively) and heart from adult (age 6-8 mo) and aged (age 22 mo) female rats. All animals received dexamethasone (Dex) in their drinking water (0.77 +/- 0.10 and 0.80 +/- 0.08 mg/day per adult and aged rat, respectively) for 5 days. Dex caused an increase in both GS activity and GS mRNA in fast-twitch and slow-twitch skeletal muscles from adult and aged rats. In contrast, Dex increased GS activity in heart of adult rats, without any concomitant change in GS mRNA levels. Furthermore, Dex did not affect GS activity in aged heart. Thus the responsiveness of GS to an excess of glucocorticoids is preserved in skeletal muscle but not in heart from aged animals.

scholarly journals Calsequestrin Distribution, Structure and Function, Its Role in Normal and Pathological Situations and the Effect of Thyroid Hormones

2011 ◽  
pp. 439-452 ◽  
Author(s):  
P. NOVÁK ◽  
T. SOUKUP
Keyword(s):  
Thyroid Hormones ◽  
Calcium Binding ◽  
Skeletal Muscles ◽  
Scientific Community ◽  
Cardiac Tissue ◽  
Structure And Function ◽  
Multiple Roles ◽  
Important Regulator ◽  
Slow Twitch ◽  
And Function

Calsequestrin is the main calcium binding protein of the sarcoplasmic reticulum, serving as an important regulator of Ca2+. In mammalian muscles, it exists as a skeletal isoform found in fast- and slow-twitch skeletal muscles and a cardiac isoform expressed in the heart and slow-twitch muscles. Recently, many excellent reviews that summarised in great detail various aspects of the calsequestrin structure, localisation or function both in skeletal and cardiac muscle have appeared. The present review focuses on skeletal muscle: information on cardiac tissue is given, where differences between both tissues are functionally important. The article reviews the known multiple roles of calsequestrin including pathology in order to introduce this topic to the broader scientific community and to stimulate an interest in this protein. Newly we describe our results on the effect of thyroid hormones on skeletal and cardiac calsequestrin expression and discuss them in the context of available literary data on this topic.

scholarly journals Activity of mu- and m-calpain in regenerating fast and slow twitch skeletal muscles.

1996 ◽  
Vol 43 (4) ◽  
pp. 693-700 ◽  
Author(s):  
J Moraczewski ◽  
E Piekarska ◽  
M Zimowska ◽  
M Sobolewska
Keyword(s):  
Intracellular Calcium ◽  
Soleus Muscle ◽  
Muscle Regeneration ◽  
Skeletal Muscles ◽  
Extensor Digitorum Longus ◽  
Extensor Digitorum ◽  
Slow Twitch ◽  
Edl Muscle ◽  
Calpain Ii ◽  
Complete Regeneration

Calpains--non-lysosomal intracellular calcium-activated neutral proteinases, form a family consisting of several distinct members. Two of the isoenzymes: mu (calpain I) and m (calpain II) responded differently to the injury during complete regeneration of Extensor digitorum longus (EDL) muscle and partial regeneration of Soleus muscle. In the crushed EDL the level of m-calpain on the 3rd and 7th day of regeneration was higher than in non-operated muscles, whereas the activity of this calpain in injured Soleus decreased. The level of mu-calpain in EDL oscillated irregularly during regeneration whereas in Soleus of both injured and contralateral muscles its level rapidly rose. Our results support the hypothesis that m-calpain is involved in the process of fusion of myogenic cells whereas mu-calpain plays a significant but indirect role in muscle regeneration.

Electrolytes in slow and fast muscle fibers of humans at rest and with dynamic exercise

1983 ◽  
Vol 245 (1) ◽  
pp. R25-R31 ◽  
Author(s):  
G. Sjogaard
Keyword(s):  
Skeletal Muscles ◽  
Vastus Lateralis ◽  
Fiber Types ◽  
Triceps Brachii ◽  
Sodium Potassium ◽  
Mean Values ◽  
Fiber Composition ◽  
Slow Twitch ◽  
Fast Twitch ◽  
Muscle Fiber Membrane

Sodium, potassium, and magnesium were analyzed in human slow-twitch (ST) and fast-twitch (FT) skeletal muscles. In contrast to other species, no relation was found between fiber composition and electrolyte distribution. In soleus (S), vastus lateralis (VL), and triceps brachii (TB) the overall mean values for 6 men and 6 women were 44 mmol K/100 g dry wt and 11 mmol Na/100 g dry wt; the intracellular concentrations were 161 mmol K/l and 26 mmol Na/l with no differences between the muscles. Analysis of fragments of single ST and FT fibers from each of the muscles also showed no difference between the fiber types in Na and K content. Small differences were seen between the muscles with regard to Mg, but these were not related to fiber composition compared with other species. During exercise to exhaustion (3 bouts of bicycling for 3 min at 325-395 W, 6 men) the extracellular electrolyte concentrations for Na, K, and Mg increased from 134 to 140, 4.5 to 5.8, and 0.75 to 0.87 mmol/l, respectively (P less than 0.05). In VL Na content increased from 9.8 to 16.5 mmol/100 g dry wt, while intracellular [Na] remained constant. In contrast, intracellular [K] decreased from 161 to 141 mmol/l (P less than 0.05). No such changes occurred in TB. In concert with other studies the present changes in electrolytes in the working muscles indicate that muscle fatigue may be related to changes at the muscle fiber membrane.

scholarly journals Comparative analysis of the transcriptomes of EDL, psoas, and soleus muscles from mice

BMC Genomics ◽  
2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Pabodha Hettige ◽  
Uzma Tahir ◽  
Kiisa C. Nishikawa ◽  
Matthew J. Gage
Keyword(s):  
Skeletal Muscles ◽  
Striated Muscle ◽  
Fiber Type ◽  
Expression Patterns ◽  
Fiber Types ◽  
Muscle Adaptation ◽  
Myosin Heavy Chain Isoform ◽  
Genes Encoding ◽  
Slow Twitch ◽  
Fast Twitch

Abstract Background Individual skeletal muscles have evolved to perform specific tasks based on their molecular composition. In general, muscle fibers are characterized as either fast-twitch or slow-twitch based on their myosin heavy chain isoform profiles. This approach made sense in the early days of muscle studies when SDS-PAGE was the primary tool for mapping fiber type. However, Next Generation Sequencing tools permit analysis of the entire muscle transcriptome in a single sample, which allows for more precise characterization of differences among fiber types, including distinguishing between different isoforms of specific proteins. We demonstrate the power of this approach by comparing the differential gene expression patterns of extensor digitorum longus (EDL), psoas, and soleus from mice using high throughput RNA sequencing. Results EDL and psoas are typically classified as fast-twitch muscles based on their myosin expression pattern, while soleus is considered a slow-twitch muscle. The majority of the transcriptomic variability aligns with the fast-twitch and slow-twitch characterization. However, psoas and EDL exhibit unique expression patterns associated with the genes coding for extracellular matrix, myofibril, transcription, translation, striated muscle adaptation, mitochondrion distribution, and metabolism. Furthermore, significant expression differences between psoas and EDL were observed in genes coding for myosin light chain, troponin, tropomyosin isoforms, and several genes encoding the constituents of the Z-disk. Conclusions The observations highlight the intricate molecular nature of skeletal muscles and demonstrate the importance of utilizing transcriptomic information as a tool for skeletal muscle characterization.

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