Abstract
We reported in the previous paper (FUJINO et al., 1961) the phenomenon that, after the completion of immersion in a hypertonic glycerol-Ringer, fibers of frog skeletal muscle give a selective inhibition of contraction in the presence of action potential. In the present paper, the original results on this description are presented, and several observations on the mechanism of the phenomenon are also given:(1) A quite similar phenomenon occurs when urea is substituted for glycerol, indicating that the phenomenon can be produced regardless of the kind of non-electrolyte used;(2) an inhibition of contraction due to the addition of glycerol followed by its removal is observable in crab leg muscle fiber and in frog stomach, where it occurs relatively obscurely, but it is not found in heart ventricle of frog. From the present results and other experimental observations by us, it is deduced that the phenomenon can occur widely in various kinds of muscle cell regardless of whether the transverse tubule system exists or not, two factors are considered to be essential for the appearance of the phenomenon:(1) penetrability of the substance or non-electrolyte used through ‘membrane’ system, which might be in contact with extracellular fluid and (2) osmotic pressure.
