title: Functional Segregation within the Muscles of Aquatic Propulsion in the Asiatic Water Monitor (Varanus salvator).
abstract: Water monitor lizards (Varanus salvator) swim using sinusoidal oscillations generated at the base of their long (50% of total body length) tail. In an effort to determine which level of the structural/organizational hierarchy of muscle is associated with functional segregation between the muscles of the tail base, an array of muscle features-myosin heavy chain profiles, enzymatic fiber types, twitch and tetanic force production, rates of fatigue, muscle compliance, and electrical activity patterns-were quantitated. The two examined axial muscles, longissimus, and iliocaudalis, were generally similar at the molecular, biochemical, and physiological levels, but differed at the biomechanics level and in their activation pattern. The appendicular muscle examined, caudofemoralis, differed from the axial muscles particularly at the molecular and physiological levels, and it exhibited a unique compliance profile and pattern of electrical activation. There were some apparent contradictions between the different structural/organizational levels examined. These contradictions, coupled with a unique myosin heavy chain profile, lead to the hypothesis that there are previously un-described molecular/biochemical specializations within varanid skeletal muscles.
authors.affiliation: Department of Anatomy, Kirksville College of Osteopathic Medicine, A.T. Still University of Health Sciences Kirksville, MO, USA.
authors.forename: Bruce A
authors.initials: BA
authors.lastname: Young
authors.affiliation: Department of Physical Therapy, University of Massachusetts Lowell Lowell, MA, USA.
authors.forename: Jessica
authors.initials: J
authors.lastname: Dumais
authors.affiliation: Department of Physical Therapy, University of Massachusetts Lowell Lowell, MA, USA.
authors.forename: Nicholas
authors.initials: N
authors.lastname: John
authors.affiliation: Department of Physical Therapy, University of Massachusetts Lowell Lowell, MA, USA.
authors.forename: Brandon
authors.initials: B
authors.lastname: Lyons
authors.affiliation: Department of Physical Therapy, University of Massachusetts Lowell Lowell, MA, USA.
authors.forename: Andrew
authors.initials: A
authors.lastname: Macduff
authors.affiliation: Department of Physical Therapy, University of Massachusetts Lowell Lowell, MA, USA.
authors.forename: Matthew
authors.initials: M
authors.lastname: Most
authors.affiliation: Department of Biosciences, College of Dentistry, Ohio State University Columbus, OH, USA.
authors.forename: Nathan A
authors.initials: NA
authors.lastname: Reiser
authors.affiliation: Department of Biosciences, College of Dentistry, Ohio State University Columbus, OH, USA.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Reiser
keywords: appendicular muscles; axial muscles; electromyography; muscle histochemistry; myosin heavy chain; whole muscle physiology; work loops