Preconditioning improves function and recovery of single muscle fibers during severe hypoxia and reoxygenation

2001 ◽  
Vol 281 (1) ◽  
pp. C142-C146 ◽  
Author(s):  
Suzanne Kohin ◽  
Creed M. Stary ◽  
Richard A. Howlett ◽  
Michael C. Hogan
Keyword(s):  
Skeletal Muscle ◽  
Ischemic Preconditioning ◽  
Muscle Fibers ◽  
Hypoxic Preconditioning ◽  
Cellular Damage ◽  
Severe Hypoxia ◽  
Single Muscle ◽  
Cell Recovery ◽  
Skeletal Muscle Fibers ◽  
Muscle Models

Reperfusion following prolonged ischemia induces cellular damage in whole skeletal muscle models. Ischemic preconditioning attenuates the deleterious effects. We tested whether individual skeletal muscle fibers would be similarly affected by severe hypoxia and reoxygenation (H/R) in the absence of extracellular factors and whether cellular damage could be alleviated by hypoxic preconditioning. Force and free cytosolic Ca2+([Ca2+]c) were monitored in Xenopus single muscle fibers ( n = 24) contracting tetanically at 0.2 Hz during 5 min of severe hypoxia and 5 min of reoxygenation. Twelve cells were preconditioned by a shorter bout of H/R 1 h before the experimental trial. In preconditioned cells, force relative to initial maximal values (P/Po) and relative peak [Ca2+]c fell ( P< 0.05) during 5 min of hypoxia and recovered during reoxygenation. In contrast, P/Po and relative peak [Ca2+]c fell more during hypoxia ( P < 0.05) and recovered less during reoxygenation ( P < 0.05) in control cells. The ratio of force to [Ca2+]c was significantly higher in the preconditioned cells during severe hypoxia, suggesting that changes in [Ca2+]c were not solely responsible for the loss in force. We conclude that 1) isolated skeletal muscle fibers contracting in the absence of extracellular factors are susceptible to H/R injury associated with changes in Ca2+handling; and 2) hypoxic preconditioning improves contractility, Ca2+ handling, and cell recovery during subsequent hypoxic insult.

scholarly journals Contractile function of single muscle fibers after hindlimb unweighting in aged rats

1998 ◽  
Vol 84 (1) ◽  
pp. 229-235 ◽  
Author(s):  
L. V. Thompson ◽  
J. A. Shoeman
Keyword(s):  
Skeletal Muscle ◽  
Functional Properties ◽  
Contractile Function ◽  
Muscle Fibers ◽  
Type I ◽  
Single Muscle ◽  
Aged Rats ◽  
Active Force ◽  
Hindlimb Unweighting ◽  
Skeletal Muscle Fibers

Thompson, L. V., and J. A. Shoeman. Contractile function of single muscle fibers after hindlimb unweighting in aged rats. J. Appl. Physiol. 84(1): 229–235, 1998.—This investigation determined how muscle atrophy produced by hindlimb unweighting (HU) alters the contractile function of single muscle fibers from older animals (30 mo). After 1 wk of HU, small bundles of fibers were isolated from the soleus muscles and the deep region of the lateral head of the gastrocnemius muscles. Single glycerinated fibers were suspended between a motor lever and force transducer, functional properties were studied, and the myosin heavy chain (MHC) composition was determined electrophoretically. After HU, the diameter of type I MHC fibers of the soleus declined (88 ± 2 vs. 80 ± 4 μm) and reductions were observed in peak active force (47 ± 3 vs. 28 ± 3 mg) and peak specific tension (Po; 80 ± 5 vs. 56 ± 5 kN/m2). The maximal unloaded shortening velocity increased. The type I MHC fibers from the gastrocnemius showed reductions in diameter (14%), peak active force (41%), and Po (24%), whereas the type IIa MHC fibers showed reductions in peak active force and Po. Thus 1 wk of inactivity has a significant effect on the force-generating capacity of single skeletal muscle fibers from older animals in a fiber type-specific manner (type I MHC > type IIa MHC > type I-IIa MHC). The decline in the functional properties of single skeletal muscle fibers in the older animals appears to be more pronounced than what has been reported in younger animal populations.

scholarly journals Human and Rodent Skeletal Muscles Express Angiotensin II Type 1 Receptors

Cells ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 1688
Author(s):  
Rafael Deminice ◽  
Hayden Hyatt ◽  
Toshinori Yoshihara ◽  
Mustafa Ozdemir ◽  
Branden Nguyen ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Angiotensin Ii ◽  
Muscle Atrophy ◽  
Muscle Fibers ◽  
Skeletal Muscle Atrophy ◽  
Type I ◽  
Single Muscle ◽  
Rat Skeletal Muscle ◽  
Skeletal Muscle Fibers

Abundant evidence reveals that activation of the renin-angiotensin system promotes skeletal muscle atrophy in several conditions including congestive heart failure, chronic kidney disease, and prolonged mechanical ventilation. However, controversy exists about whether circulating angiotensin II (AngII) promotes skeletal muscle atrophy by direct or indirect effects; the centerpiece of this debate is the issue of whether skeletal muscle fibers express AngII type 1 receptors (AT1Rs). While some investigators assert that skeletal muscle expresses AT1Rs, others argue that skeletal muscle fibers do not contain AT1Rs. These discordant findings in the literature are likely the result of study design flaws and additional research using a rigorous experimental approach is required to resolve this issue. We tested the hypothesis that AT1Rs are expressed in both human and rat skeletal muscle fibers. Our premise was tested using a rigorous, multi-technique experimental design. First, we established both the location and abundance of AT1Rs on human and rat skeletal muscle fibers by means of an AngII ligand-binding assay. Second, using a new and highly selective AT1R antibody, we carried out Western blotting and determined the abundance of AT1R protein within isolated single muscle fibers from humans and rats. Finally, we confirmed the presence of AT1R mRNA in isolated single muscle fibers from rats. Our results support the hypothesis that AT1Rs are present in both human and rat skeletal muscle fibers. Moreover, our experiments provide the first evidence that AT1Rs are more abundant in fast, type II muscle fibers as compared with slow, type I fibers. Together, these discoveries provide the foundation for an improved understanding of the mechanism(s) responsible for AngII-induced skeletal muscle atrophy.

The “KIMWIPE” Effect in Ultra-Thin Cryosections

1985 ◽  
Vol 43 ◽  
pp. 458-459
Author(s):  
I. Taylor ◽  
P. Ingram ◽  
J.R. Sommer
Keyword(s):  
Skeletal Muscle ◽  
Electrical Stimulation ◽  
Muscle Fibers ◽  
Ice Crystals ◽  
Crystal Formation ◽  
Ice Crystal ◽  
Thin Sections ◽  
Skeletal Muscle Fibers ◽  
Freeze Dried ◽  
Ice Crystal Formation

In studying quick-frozen single intact skeletal muscle fibers for structural and microchemical alterations that occur milliseconds, and fractions thereof, after electrical stimulation, we have developed a method to compare, directly, ice crystal formation in freeze-substituted thin sections adjacent to all, and beneath the last, freeze-dried cryosections. We have observed images in the cryosections that to our knowledge have not been published heretofore (Figs.1-4). The main features are that isolated, sometimes large regions of the sections appear hazy and have much less contrast than adjacent regions. Sometimes within the hazy regions there are smaller areas that appear crinkled and have much more contrast. We have also observed that while the hazy areas remain still, the regions of higher contrast visibly contract in the beam, often causing tears in the sections that are clearly not caused by ice crystals (Fig.3, arrows).

Effect of External Calcium and other Divalent Cations on K+ Contractures in Denervated Slow Skeletal Muscle Fibers of the Frog

2019 ◽  
Author(s):  
Leonardo Hernández
Keyword(s):  
Skeletal Muscle ◽  
Binding Capacity ◽  
Divalent Cations ◽  
Muscle Fibers ◽  
Free Calcium ◽  
Slow Skeletal Muscle ◽  
Skeletal Muscle Fibers ◽  
Free Calcium Concentration ◽  
Chronic Denervation ◽  
Denervated Muscles

The influence of Ca2+ and other divalent cations on contractile responses of slow skeletal muscle fibers of the frog (Rana pipiens) under conditions of chronic denervation was investigated.Isometric tension was recorded from slow bundles of normal and denervated cruralis muscle in normal solution and in solutions with free calcium concentration solution or in solutions where other divalent cations (Sr2+, Ni2+, Co2+ or Mn2+) substituted for calcium. In the second week after nerve section, in Ca2+-free solutions, we observed that contractures (evoked from 40 to 80 mM-K+) of non-denervated muscles showed significantly higher tensions (p<0.05), than those from denervated bundles. Likewise, in solutions where calcium was substituted by all divalent cations tested, with exception of Mn2+, the denervated bundles displayed lower tension than non-denervated, also in the second week of denervation. In this case, the Ca2+ substitution by Sr2+ caused the higher decrease in tension, followed by Co2+ and Ni2+, which were different to non-denervated bundles, as the lowest tension was developed by Mn2+, followed by Co2+, and then Ni2+ and Sr2+. After the third week, we observed a recovery in tension. These results suggest that denervation altering the binding capacity to divalent cations of the voltage sensor.

scholarly journals NOS I IN PIGEON SKELETAL MUSCLE FIBERS*

1997 ◽  
Vol 75 ◽  
pp. 36
Author(s):  
R Gossrau ◽  
Z Grozdanovic
Keyword(s):  
Skeletal Muscle ◽  
Muscle Fibers ◽  
Skeletal Muscle Fibers

scholarly journals Development of a human neuromuscular tissue-on-a-chip model on a 24-well-plate-format compartmentalized microfluidic device

Lab on a Chip ◽  
2021 ◽  
Author(s):  
Kazuki Yamamoto ◽  
Nao Yamaoka ◽  
Yu Imaizumi ◽  
Takunori Nagashima ◽  
Taiki Furutani ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Microfluidic Device ◽  
Motor Neurons ◽  
Muscle Fibers ◽  
Three Dimensional ◽  
Tissue Model ◽  
Skeletal Muscle Fibers

A three-dimensional human neuromuscular tissue model that mimics the physically separated structures of motor neurons and skeletal muscle fibers is presented.

scholarly journals Glycogenin is Dispensable for Glycogen Synthesis in Human Muscle, and Glycogenin Deficiency Causes Polyglucosan Storage

2019 ◽  
Vol 105 (2) ◽  
pp. 557-566 ◽  
Author(s):  
Kittichate Visuttijai ◽  
Carola Hedberg-Oldfors ◽  
Christer Thomsen ◽  
Emma Glamuzina ◽  
Cornelia Kornblum ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Skeletal Muscle ◽  
Western Blot ◽  
Cardiac Muscle ◽  
Glycogen Synthesis ◽  
Muscle Fibers ◽  
Human Muscle ◽  
Missense Mutations ◽  
Skeletal Muscle Fibers ◽  
Glycogen Biosynthesis

Abstract Context Glycogenin is considered to be an essential primer for glycogen biosynthesis. Nevertheless, patients with glycogenin-1 deficiency due to biallelic GYG1 (NM_004130.3) mutations can store glycogen in muscle. Glycogenin-2 has been suggested as an alternative primer for glycogen synthesis in patients with glycogenin-1 deficiency. Objective The objective of this article is to investigate the importance of glycogenin-1 and glycogenin-2 for glycogen synthesis in skeletal and cardiac muscle. Design, Setting, and Patients Glycogenin-1 and glycogenin-2 expression was analyzed by Western blot, mass spectrometry, and immunohistochemistry in liver, heart, and skeletal muscle from controls and in skeletal and cardiac muscle from patients with glycogenin-1 deficiency. Results Glycogenin-1 and glycogenin-2 both were found to be expressed in the liver, but only glycogenin-1 was identified in heart and skeletal muscle from controls. In patients with truncating GYG1 mutations, neither glycogenin-1 nor glycogenin-2 was expressed in skeletal muscle. However, nonfunctional glycogenin-1 but not glycogenin-2 was identified in cardiac muscle from patients with cardiomyopathy due to GYG1 missense mutations. By immunohistochemistry, the mutated glycogenin-1 colocalized with the storage of glycogen and polyglucosan in cardiomyocytes. Conclusions Glycogen can be synthesized in the absence of glycogenin, and glycogenin-1 deficiency is not compensated for by upregulation of functional glycogenin-2. Absence of glycogenin-1 leads to the focal accumulation of glycogen and polyglucosan in skeletal muscle fibers. Expression of mutated glycogenin-1 in the heart is deleterious, and it leads to storage of abnormal glycogen and cardiomyopathy.

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