J. Maylie

TL;DR: The intrinsic fiber absorbance, defined operationally as log10 of the ratio of incident light to transmitted light intensity, was similar in intact and cut preparations, as were the changes that accompanied stimulation; changes are probably due to a progressive alteration in the internal state of the cut fibers.

TL;DR: The Ca indicator antipyrylazo III was introduced into cut frog twitch fibers by diffusion, with a wavelength dependence that nearly matched a cuvette Ca-difference spectrum and the peak amplitude of this Ca signal depended on the indicator concentration in a roughly parabolic manner.

TL;DR: If the pH gradients are small, the same expression for the apparent diffusion constant of protons can be derived without such constraints on the values of the pK's.

TL;DR: The Ca indicator arsenazo III was introduced into cut frog twitch fibers by diffusion from end-pool segments rendered permeable by saponin and the active Ca and dichroic signals were similar in the two preparations, which indicates that arsenazoIII undergoes the same changes in absorbance and orientation in both cut and intact fibers.

TL;DR: The Ca indicator tetramethylmurexide was introduced into cut fibers, mounted in a double-Vaseline-gap chamber, by diffusion from the end- pool solutions and there was a rapid transient change in indicator absorbance followed by a maintained change of opposite sign.