1 / 13

Maintenance of Bat Skeletal Muscle during Hibernation

Maintenance of Bat Skeletal Muscle during Hibernation. Kevin Ornee. Exercise. Change in skeletal muscle is dependent on use. Two muscle types: Fast (more glycolytic) Slow (more oxidative) Aerobic exercise increases mass and oxidative capacity of the muscle.

keane-wolfe
Download Presentation

Maintenance of Bat Skeletal Muscle during Hibernation

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Maintenance of Bat Skeletal Muscle during Hibernation Kevin Ornee

  2. Exercise • Change in skeletal muscle is dependent on use. • Two muscle types: Fast (more glycolytic) Slow (more oxidative) • Aerobic exercise increases mass and oxidative capacity of the muscle. • Disuse decreases mass and oxidative capacity of the muscle.

  3. Atrophy • Humans experience profound disuse atrophy up to 50% reduction in mass in just 4 weeks. • Hibernating animals show reduced <30% to no atrophy over a period of 6 months. • Hibernating animals show increased oxidative capacity.

  4. Hibernation • Freezing temperatures, photoperiod and lack of food. • Torpor – Enter state of reduced body temp and metabolic rate. • Thermogenesis – quivering rapidly increases body temp.

  5. Hibernation Habits • Hang upside-down from ceiling of caves • Cave shelter 5-10°C • Arousal and relocation observed • Drafts/cold spots • Cold temps, food unlikely • Great risk of starvation

  6. Weight and Energy Issues • Little brown bats begin hibernation from 20-25 grams and lose ~ 35% of their body mass. • Able to fly upon arousal, great strength and fatigue resistance.

  7. Flight • Pectoralis muscle, highest oxidative capacity of mammalian skeletal muscle >90%. • Over six month hibernation period there is no change in fiber makeup of the pectoralis.

  8. Atrophy Prevention • May be attributed to many factors: • An adaptation • Tension created by wings • Muscle activity during arousal and relocation

  9. Flight Experiment • Limiting flight to stimulate disuse atrophy, small cage, large cage and wild. • Expected reduction in strength and oxidative capacity. • Contractile force measured. • Section of the muscle will be stained and analyzed to determine cross sectional area. • Immunoblots for CS and Akt.

  10. Wing Tension Experiment • While hanging, tension created by bats wings may initiate exercise feedback. • Increasing and decreasing tension would be expected to decrease and increase atrophy, respectively.

  11. Relocation Telemetry • Hibernation induced in cold rooms. • Bats subject to cold, drafty conditions are expected to relocate. • Bats with available food expected to benefit if aroused. • Control monitored for muscle activity during a full six month hibernation. • Electromyography use to remotely monitor muscle activity.

  12. Benefits • Comparison of bat to other hibernating species should show an increase in the mechanism to prevent disuse atrophy. • Application to human skeletal muscle would greatly benefit clinical orthopedics and space exploration.

More Related