Seasonal biochemical plasticity of a flight muscle in a bat, Murina leucogaster

Kim, Mi‐Hyun; Park, Kyoungsook; Gwag, Byoung Joo; Jung, Noh-Pal; Oh, Yung Keun; Shin, Hyung‐Cheul; Choi, Inho

doi:10.1016/s1095-6433(00)00203-8

Cited by 20 publications

(10 citation statements)

References 11 publications

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“…The majority of studies conducted on hamsters (Deveci and Egginton, 2002b;James et al, 2011), ground squirrels (Cotton and Harlow, 2010;Gao et al, 2012;James et al, 2013;Nowell et al, 2011;Steffen et al, 1991;Yang et al, 2014) and bats (Kim et al, 2000;Lee et al, 2008;Yacoe, 1983a) have shown relatively minor changes in muscle mass and protein content during hibernation, with most reporting 5-30% decreases in mass and 5-15% decreases in protein (Table 1). There is, however, some variation depending on species, specific muscles and sampling period.…”

Section: Morphological Changes During Hibernationmentioning

confidence: 99%

“…Glucagon and noradrenaline (norepinephrine) are more effective stimulators of fatty acid mobilization during hibernation (MoreauHamsany et al, 1988), while delivery of fatty acids is enhanced by the upregulation of fatty acid binding proteins in both bats and ground squirrels (Eddy and Storey, 2004;Hittel and Storey, 2001). Additionally, citrate synthase activity is enhanced during hibernation in skeletal muscle of bats (Kim et al, 2000).…”

Section: Morphological Changes During Hibernationmentioning

confidence: 99%

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Skeletal muscle mass and composition during mammalian hibernation

Cotton

2016

Journal of Experimental Biology

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Hibernation is characterized by prolonged periods of inactivity with concomitantly low nutrient intake, conditions that would typically result in muscle atrophy combined with a loss of oxidative fibers. Yet, hibernators consistently emerge from winter with very little atrophy, frequently accompanied by a slight shift in fiber ratios to more oxidative fiber types. Preservation of muscle morphology is combined with downregulation of glycolytic pathways and increased reliance on lipid metabolism instead. Furthermore, while rates of protein synthesis are reduced during hibernation, balance is maintained by correspondingly low rates of protein degradation. Proposed mechanisms include a number of signaling pathways and transcription factors that lead to increased oxidative fiber expression, enhanced protein synthesis and reduced protein degradation, ultimately resulting in minimal loss of skeletal muscle protein and oxidative capacity. The functional significance of these outcomes is maintenance of skeletal muscle strength and fatigue resistance, which enables hibernating animals to resume active behaviors such as predator avoidance, foraging and mating immediately following terminal arousal in the spring.

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Section: Morphological Changes During Hibernationmentioning

confidence: 99%

Section: Morphological Changes During Hibernationmentioning

confidence: 99%

Skeletal muscle mass and composition during mammalian hibernation

Cotton

2016

Journal of Experimental Biology

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“…Unloading in these studies was imposed by limb suspension, casting, orthopedic injury, bed rest, or decreased gravity. Otber mammalian hibernators are also susceptible to disuse atrophy, including bats (Kim et al 2000), hamsters (Wickler et al 1987), and ground squirrels (Wickler et al 1991). Muscle atrophy results in a significant loss of strength and motor fimction due to several factors.…”

Section: Introductionmentioning

confidence: 99%

Minimal Seasonal Alterations in the Skeletal Muscle of Captive Brown Bears

Hershey

Robbins²,

Nelson³

et al. 2008

Physiological and Biochemical Zoology

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Previous studies on wild black bears (Ursus americanus) have shown that skeletal muscle morphology, composition, and overall force-generating capacity do not differ drastically between seasons despite prolonged inactivity during hibernation. However, the amount and characteristics of the seasonal variations were not consistent in these studies. The goals of this study were to compare the amount of muscle atrophy in captive brown bears (Ursus arctos) with that observed in wild black bears and measure seasonal differences in twitch characteristics. Samples from the biceps femoris muscle were collected during the summer and winter. Protein concentration, fiber-type composition, and fiber cross-sectional area were measured along with twitch characteristics. The protein concentration of the winter samples was 8.2% lower than that of the summer samples; fiber cross-sectional area and the relative proportion of fast and slow fibers remained unchanged between seasons. Myosin heavy chain isoforms I, IIa, and IIx were identified by immunoblotting and electrophoresis, and the proportions did not change between seasons. The half-rise time in the twitch contractions increased in winter relative to summer samples, which is unexpected under disuse conditions. These results agreed with a study that showed minimal skeletal muscle atrophy between seasons in wild black bears.

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“…Squirrels were grouped into six periods: spring (Spr), summer (Sum), autumn (Aut), hibernating for 2 months (H), and aroused after 2 days (A2) and after 14 days (A14) from more than 3 months of hibernation. levels continue into the summer (Kim et al 2000). SOL is a slowtwitch muscle predominantly consisting of slow-twitch oxidative fibers with high Mb content and mitochondrial density.…”

Section: Discussionmentioning

confidence: 99%

Seasonal oxidative capacity of skeletal muscles in hibernating Daurian ground squirrels (Spermophilus dauricus)

et al. 2015

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We investigated the mechanism of high oxidative capacity of skeletal muscles in hibernating Daurian ground squirrels (Spermophilus dauricus Brandt, 1843). Myoglobin (Mb) levels, as well as citrate synthase and lactate dehydrogenase (LDH) activities, were measured by spectrophotometry. Mb content in the soleus (SOL) muscle lasted from the beginning of hibernation to spring. Mb content in SOL was 87% higher in the hibernating group than in the summer group. Mb content in the extensor digitorum longus (EDL) muscle stayed at similar levels during the different periods of the year. Citrate synthase activity in SOL was 30% higher in the hibernating group than in the summer group. Meanwhile, citrate synthase activity in EDL did not change during hibernation. LDH activity in SOL was not different between the hibernating group and the summer active group, whereas LDH activity in EDL increased significantly (up to 11%) in the 2 days arousal after hibernation group compared with the hibernating group. We conclude that high oxidative capacity is provided by increased oxygen storage capacity of slow-twitch muscle fibers rather than from fast-twitch muscle fibers in hibernating animals. Résumé :Nous avons examiné le mécanisme qui sous-tend la capacité oxydative élevée des muscles squelettiques chez des spermophiles de Daourie (Spermophilus dauricus Brandt, 1843) hibernants. Les teneurs en myoglobine (Mb), ainsi que les activités de la citrate-synthase et de la lactate-déshydrogénase (LDH) ont été mesurées par spectrophotométrie. Les teneurs en Mb dans le muscle soléaire (SOL) persistaient du début de l'hibernation jusqu'au printemps. Les teneurs en Mb dans le SOL étaient de 87 % plus grandes dans le groupe hibernant que dans le groupe d'été. La Mb dans le muscle long extenseur du doigt (EDL) se maintenait à des teneurs semblables durant toutes les saisons de l'année. L'activité de la citrate-synthase dans le SOL était de 30 % plus grande dans le groupe hibernant que dans le groupe estival, alors que dans l'EDL, elle ne changeait pas durant l'hibernation. Il n'y avait pas de différence sur le plan de l'activité de la LDH dans le SOL entre le groupe hibernant et le groupe estival, alors que dans l'EDL, l'activité de la LDH augmentait de manière significative (jusqu'à 11 %) dans le groupe observé 2 jours après le réveil suivant l'hibernation par rapport au groupe hibernant. Nous concluons que la capacité oxydative élevée chez les animaux hibernants est assurée par une capacité de stockage d'oxygène accrue dans les fibres musculaires à contraction lente plutôt que par les fibres musculaires à contraction rapide. [Traduit par la Rédaction]

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Seasonal biochemical plasticity of a flight muscle in a bat, Murina leucogaster

Cited by 20 publications

References 11 publications

Skeletal muscle mass and composition during mammalian hibernation

Skeletal muscle mass and composition during mammalian hibernation

Minimal Seasonal Alterations in the Skeletal Muscle of Captive Brown Bears

Seasonal oxidative capacity of skeletal muscles in hibernating Daurian ground squirrels (Spermophilus dauricus)

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