Photopot isotonic myogram.

Ross, S M; Brust, M

doi:10.1152/jappl.1966.21.1.293

Cited by 4 publications

(1 citation statement)

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“…The other end of the muscle was tied directly to a fine golden chain which was attached to a light isotonic lever. The lever system was designed for studies on skeletal muscle (20); for our experiments the lever arm was made of magnesium and somewhat reduced in length and mass. The extent to which the effective mass of the lever caused variations in load of afterloaded contractions can be seen in the records of such contractions.…”

Section: Methodsmentioning

confidence: 99%

Some Mechanical Properties of Isolated Mammalian Cardiac Muscle

Hoffman

Bassett

Bartelstone

1968

Circulation Research

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Isolated preparations of mammalian cardiac muscle have been employed to study possible mechanisms responsible for changes in diastolic compliance. Muscles have been studied at rest and during isometric and afterloaded contractions, at fixed initial length and during programmed, cyclic changes in length, and under the influence of paired stimulation, catecholamines, and elevated extracellular calcium concentrations. The results obtained indicate that, although there is a series viscous element in cardiac muscle, which accounts for stress-relaxation, some changes in compliance apparently result from alterations in the extensibility of the contractile element. This conclusion is based primarily on experiments showing shifts in the apex of the length-tension curve produced by action of inotropic agents which alter diastolic compliance and on experiments showing that the rate and extent of relaxation of afterloaded contractions depend on the extent of shortening during contraction. • During the past forty years a variety of considerations have suggested that the diastolic pressure-volume relationship for the mammalian ventricle might vary as a result of some change in the characteristics of the myocardium (1-8). Moreover, it was recognized early that under appropriate conditions variability in the pressure-volume relationship would influence both the performance of the heart as well as any evaluation of performance which employed measurement of enddiastolic pressure as an index of fiber length. A change in the pressure-volume or lengthtension relationship might result either from an alteration in the contractile elements or

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Section: Methodsmentioning

confidence: 99%