Estimation of changes in single muscle fibre diameter in different solutions by diffraction studies.

Studies of the effects of varying tonicity on the contraction of muscle fibres requires a knowledge of the corresponding changes in fibre diameters, if the observed mechanical changes are to be attributed to various factors, including that of the interfilamental spacing. Hitherto, measurements of such changes in fibre diameters involved tedious measurements of the diameters of the fibres at numerous points along its length. We now describe a technique whereby the change in fibre diameter can be deduced from measurements of the corresponding intensity ratio of laser diffraction lines when the fibre is bathed in solutions of differing tonicities.