Non-linear myofilament elasticity in frog intact muscle fibres

Non-linear myofilament elasticity in frog intact muscle fibres.

The aim of the present investigation was to elucidate the elastic properties of the myofilaments during tetanic activity in striated muscle. The study was carried out on intact single muscle fibres from the anterior tibialis muscle of Rana temporaria (2.0-2.5 degrees C). The instantaneous stiffness was measured as the change in force that occurred in response to a high-frequency (2-4 kHz) lengt...

There is no experimental evidence for non-linear myofilament elasticity in skeletal muscle.

Information on the stiffness of the actin and myosin filaments is a key parameter in the study of muscle contraction. For example, the number of motors attached to actin in each half-sarcomere of a muscle fibre can be obtained from measurements of the half-sarcomere stiffness, provided that the compliances of the actin and myosin filaments are known (Piazzesi et al., 2007). The stress–strain re...

Myofilament Ca2+ sensitivity in intact versus skinned rat ventricular muscle.

The Ca2+ sensitivity of myofilaments was compared before and after skinning in the same rat trabeculae at a diastolic sarcomere length of 2.2 to 2.3 microns. Trabeculae from rat right ventricle were loaded with fura-2 salt by iontophoretic microinjection, and [Ca2+]i was determined from the epifluorescence at 510 nm when excited at 340 and 380 nm. Steady-state activation was achieved by stimula...

Supplementary Information Significant Impact on Muscle Mechanics of Small Non-linearities in Myofilament Elasticity

Calcium Sparks in Intact Skeletal Muscle Fibers of the Frog

Calcium sparks were studied in frog intact skeletal muscle fibers using a home-built confocal scanner whose point-spread function was estimated to be approximately 0.21 microm in x and y and approximately 0.51 microm in z. Observations were made at 17-20 degrees C on fibers from Rana pipiens and Rana temporaria. Fibers were studied in two external solutions: normal Ringer's ([K(+)] = 2.5 mM; es...