Polarization changes in light diffracted from contracting muscle fibers |
| |
Authors: | A F Leung M K Cheung |
| |
Institution: | (1) Department of Physics, The Chinese University of Hong Kong, Hong Kong |
| |
Abstract: | Single fibers were isolated from the semitendinosus muscle of frog and illuminated with an He-Ne laser. The polarization of
the laser beam was varied by a photoelastic modulator. The time course of the degree of polarization of light diffracted from
the muscle fiber during an isometric contraction was measured directly with a time resolution of 1 ms. Tension, sarcomere
length, and diffraction intensity were also measured. During the contraction cycle, the degree of polarization of the active
fiber exhibited a biphasic variation relative to that of the resting fiber. Analysis identifies the movement of heavy meromyosin
toward actin and the rise in myoplasmic calcium ion concentration as the main contributors to the polarization transient of
active fibers. A quantitative theory describing the polarized diffraction from muscle fibers is formulated. There is good
agreement between the theory and measurements. |
| |
Keywords: | Striated muscle fiber light diffraction light polarization photoarray photoelastic modulator heavy meromyosin |
本文献已被 SpringerLink 等数据库收录! |