Energetics

ATP Supply and Demand

One continuing research interest in our laboratory is the adaptive plasticity of vertebrate skeletal muscle. How does muscle adapt to both the nature and intensity of the demands placed upon it (including those of different sized animals)?  These changes involve changes in metabolic properties such as the densities of capillaries and mitochondria as well as contractile properties such as the force, velocity and efficiency of contraction.  Skeletal muscle is remarkable in part because shifts in very few structural components result in mechanical outcomes as varied as burst power, sound production and posture, to name just a few.

One problem that all muscles must “solve” is the balance of energy supply and demand. Together with Kevin Conley at the University of Washington, we have used the tail-shaker muscle of the Western Diamondback rattlesnake as a model system. High frequency muscle use (up to 90Hz) demands high densities of both mitochondria and sarcoplasmic reticulum as well. By coupling NMR spectroscopy to investigate high energy phosphate regulation of aerobic muscle energetics with quantitative electron microscopy, we have investigated this muscle, which is among the most frugal of all muscles in its use of energy. However, surprisingly, it relies on what textbooks may label as “anaerobic glycolysis” to supply part of those steady-state ATP demands.

 

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Other Interests:

Allometry | Muscles as Springs | Clinical Research