Energy use and work output by cross-bridges in fast- and slow-twitch muscles

Funded Activity Summary

All voluntary movement is produced by the action of skeletal muscles. The muscles provide the mechanical power required to move the limbs and the body. To do so, they require energy which is ultimately derived from the breakdown of food. Therefore, we can describe the fundamental process underlying muscular contraction as the conversion of energy from a chemical form into a mechanical form. This project investigates the relationship between the breakdown of molecules that provide energy and the production of mechanical energy or work. Normal contraction involves many cyclic interactions between two proteins, actin and myosin. Each cycle produces a tiny force that contributes to the shortening of the muscle. For over 30 years, it has been thought that energy required for each force producing cycle was provided by the breakdown of one energy-providing molecule, called ATP. Almost all current models of muscle contraction are based on this idea. Recently, data from studies using isolated actin and myosin and observing their interaction in vitro have indicated that many force-producing cycles may be performed with the energy from just one ATP. If this is correct, it will revolutionise our ideas about the way muscles convert chemical energy into mechanical energy. However, the interaction of proteins in a dish is far removed from a normal muscle and the aim of this project is to determine the relationship between force producing cycles and energy use in intact muscles. If multiple force-producing cycles can be powered by one ATP molecule in intact muscle too, then the current idea that the biochemical processes that release energy from ATP are intimately linked to the mechanical changes in myosin that occur as it produces force will be untenable. In short, we will have to rediscover how muscles convert chemical energy into mechanical energy and find out how that energy can be stored from one force-producing cycle to the next.

Funded Activity Details

Start Date: 01-01-2000

End Date: 01-01-2002

Funding Scheme: NHMRC Project Grants

Funding Amount: $191,177.00

Funder: National Health and Medical Research Council

Research Topics

ANZSRC Field of Research (FoR)

Medical biotechnology diagnostics (incl. biosensors)

ANZSRC Socio-Economic Objective (SEO)

There are no SEO codes available for this funding activity

Other Keywords

contraction mechanisms | muscle fatigue | muscle heat production | muscular dystrophy | post-viral fatigue | skeletal muscle

Related Links