scholarly journals Aerobic characteristics of red kangaroo skeletal muscles: is a high aerobic capacity matched by muscle mitochondrial and capillary morphology as in placental mammals?

2004 ◽  
Vol 207 (16) ◽  
pp. 2811-2821 ◽  
Author(s):  
T. J. Dawson
Keyword(s):  
Aerobic Capacity ◽  
Skeletal Muscles ◽  
Red Kangaroo

Load-matched acute and chronic exercise induce changes in mitochondrial biogenesis and metabolic markers

2021 ◽  
Author(s):  
Natalia Almeida Rodrigues ◽  
Claudio Alexandre Gobatto ◽  
Lucas Dantas Maia Forte ◽  
Filipe Antônio de Barros Sousa ◽  
Adriana Souza Torsoni ◽  
...  
Keyword(s):  
Aerobic Capacity ◽  
Skeletal Muscles ◽  
Acute Exercise ◽  
Citrate Synthase ◽  
Liver Glycogen ◽  
Chronic Exercise ◽  
Total Load ◽  
Metabolic Markers ◽  
Target Proteins ◽  
Glycogen Stores

We investigated the effects of the acute and chronic exercise, prescribed in different intensity zones, but with total load-matched on mitochondrial markers (COX-IV, Tfam, and citrate synthase (CS) activity in skeletal muscles, heart, and liver), glycogen stores, aerobic capacity and anaerobic index in swimming rats. For this, two experimental designs were performed (acute and chronic efforts). Load-matched exercises were prescribed below and above and on the anaerobic threshold (AnT), determined by the Lactate Minimum test. In chronic programs, two training prescription strategies were assessed (monotonous and linear periodized model). Results show changes in glycogen stores but no modification in the COX-IV and Tfam contents after acute exercises. In the chronic protocols, COX-IV and Tfam proteins and CS adaptations were intensity and tissue dependents. Monotonous training promoted better adaptations than the periodized model. Training at 80% of the AnT improved both performance variables, emphasizing the anaerobic index, concomitant to CS and COX-IV improvement (soleus muscle). The aerobic capacity and CS activity (gastrocnemius) were increased after 120% AnT training. In conclusion, acute exercise protocol did not promote responses in mitochondrial target proteins. An intensity and tissue dependence are reported in the chronic protocols, highlighting training at 80 and 120% of the AnT. Novelty: • Load-matched acute exercise did not enhance COX-IV and Tfam contents in skeletal muscles, heart, and liver. • In chronic exercise, COX-IV, Tfam, and citrate synthase activity adaptations were intensity and tissue dependents. •Monotonous training was more efficient than the periodized linear model in adaptations of target proteins and enzymatic activity.

scholarly journals Aerobic capacities in the skeletal muscles of Weddell seals: key to longer dive durations?

2002 ◽  
Vol 205 (23) ◽  
pp. 3601-3608 ◽  
Author(s):  
S. B. Kanatous ◽  
R. W. Davis ◽  
R. Watson ◽  
L. Polasek ◽  
T. M. Williams ◽  
...  
Keyword(s):  
Aerobic Capacity ◽  
Skeletal Muscles ◽  
Marine Mammals ◽  
Fiber Type ◽  
Weddell Seal ◽  
Weddell Seals ◽  
Terrestrial Mammals ◽  
Hypoxic Conditions ◽  
Long Duration ◽  
Energy Conserving

SUMMARYIn contrast to terrestrial animals that function under hypoxic conditions but display the typical exercise response of increasing ventilation and cardiac output, marine mammals exercise under a different form of hypoxic stress. They function for the duration of a dive under progressive asphyxia,which is the combination of increasing hypoxia, hypercapnia and acidosis. Our previous studies on short-duration, shallow divers found marked adaptations in their skeletal muscles, which culminated in enhanced aerobic capacities that are similar to those of atheltic terrestrial mammals. The purpose of the present study was to assess the aerobic capacity of skeletal muscles from long-duration divers. Swimming and non-swimming muscles were collected from adult Weddell seals, Leptonychotes weddelli, and processed for morphometric analysis, enzymology, myoglobin concentrations and fiber-type distribution. The results showed that the skeletal muscles of Weddell seals do not have enhanced aerobic capacities compared with those of terrestrial mammals but are adapted to maintain low levels of an aerobic lipid-based metabolism, especially under the hypoxic conditions associated with diving. The lower aerobic capacity of Weddell seal muscle as compared with that of shorter-duration divers appears to reflect their energy-conserving modes of locomotion, which enable longer and deeper dives.

31° South: phenotypic flexibility in adaptive thermogenesis among conspecific populations of an arid-endemic bird - from organismal to cellular level

2018 ◽  
Author(s):  
Ângela M. Ribeiro ◽  
Clara Prats ◽  
Nicholas B. Pattinson ◽  
M. Thomas P. Gilbert ◽  
Ben Smit
Keyword(s):  
Aerobic Capacity ◽  
Skeletal Muscles ◽  
Cellular Level ◽  
Arid Zones ◽  
Phenotypic Flexibility ◽  
Metabolic Capacity ◽  
Adaptive Thermogenesis ◽  
Available Energy ◽  
Two Indices ◽  
Small Bird

ABSTRACTIn north-temperate small passerines, overwinter survival is associated with a reversibly increased maximum cold-induced metabolism (Msum). This strategy may incur increased energy consumption. Therefore, species inhabiting ecosystems characterized by cold winters and low productivity (i.e., low available energy) may be precluded from displaying an increase in maximum metabolic rates. To examine whether Msumis a flexible phenotype in such challenging environments, and ultimately uncover its underpinning mechanisms, we studied an arid-endemic small bird (Karoo scrub-robin) whose range spans a primary productivity and minimum temperature gradient. We measured Msum, body condition, mass of thermogenic muscles and two indices of cellular aerobic capacity from populations living in three environmentally different regions. We found that Msumwas seasonally flexible, associated with aerobic capacity of limb muscles, but not increasing with lower temperatures, as predicted. Notwithstanding, the cold limit (temperature at which birds reached their maximum metabolic capacity) decreased in winter. These results indicate that birds from arid-zones may respond to cold conditions by altering thermosensation, rather than spending energy to produce heat in skeletal muscles.

Distribution of c-protein isoforms in sarcomeres of developing chick skeletal muscle

1988 ◽  
Vol 46 ◽  
pp. 226-227
Author(s):  
D. A. Fischman ◽  
J. E. Dennis ◽  
T. Obinata ◽  
H. Takano-Ohmuro
Keyword(s):  
Skeletal Muscles ◽  
Thick Filament ◽  
Protein Isoforms ◽  
Actin Binding ◽  
Striated Muscles ◽  
C Protein ◽  
Sarcomeric Protein ◽  
Thick Filaments ◽  
Cross Bridges ◽  
Bridge Bearing

C-protein is a 150 kDa protein found within the A bands of all vertebrate cross-striated muscles. By immunoelectron microscopy, it has been demonstrated that C-protein is distributed along a series of 7-9 transverse stripes in the medial, cross-bridge bearing zone of each A band. This zone is now termed the C-zone of the sarcomere. Interest in this protein has been sparked by its striking distribution in the sarcomere: the transverse repeat between C-protein stripes is 43 nm, almost exactly 3 times the 14.3 nm axial repeat of myosin cross-bridges along the thick filaments. The precise packing of C-protein in the thick filament is still unknown. It is the only sarcomeric protein which binds to both myosin and actin, and the actin-binding is Ca-sensitive. In cardiac and slow, but not fast, skeletal muscles C-protein is phosphorylated. Amino acid composition suggests a protein of little or no αhelical content. Variant forms (isoforms) of C-protein have been identified in cardiac, slow and embryonic muscles.

The effect of ionophore A23178 on the α-actinin crosslinks in the z-band of frog skeletal muscle: An EM study

1986 ◽  
Vol 44 ◽  
pp. 154-155
Author(s):  
F.T. Llados ◽  
V. Krlho ◽  
G.D. Pappas
Keyword(s):  
Muscle Damage ◽  
Transmitter Release ◽  
Skeletal Muscles ◽  
Calcium Uptake ◽  
Muscle Membrane ◽  
Frog Skeletal Muscle ◽  
Ach Release ◽  
Sustained Action ◽  
Calcium Deposits ◽  
Intense Stimulation

It Is known that Ca++ enters the muscle fiber at the junctional area during the action of the neurotransmitter, acetylcholine (ACh). Pappas and Rose demonstrated that following Intense stimulation, calcium deposits are found In the postsynaptic muscle membrane, Indicating the existence of calcium uptake In the postsynaptic area following ACh release. In addition to this calcium uptake, when mammal Ian skeletal muscles are exposed to a sustained action of the neurotransmitter, muscle damage develops. These same effects, l.e., Increased transmitter release, calcium uptake and finally muscle damage, can be obtained by Incubating the muscle with lonophore A23178.

Comparative Morphology of Skeletal Muscles in Man and Macaque

1993 ◽  
Vol 5 (2) ◽  
pp. 137-146
Author(s):  
Seiichiro INOKUCHI ◽  
Tadanao KIMURA ◽  
Masataka SUZUKI ◽  
Junji ITO ◽  
Hiroo KUMAKURA
Keyword(s):  
Skeletal Muscles ◽  
Comparative Morphology
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