AN ATTEMPT AT ESTIMATING EXTRAFIBER FLUID IN SMALL SKELETAL MUSCLES BY A SIMPLE PHYSICAL METHOD

Abstract

Estimation of the extrafiber fluid volume in the biceps brachii muscle of the mouse was attempted by pressing the fibers into a thin layer. This caused the fluid from the spaces between the fibers to be displaced to the periphery of the fiber mass. As the thickness of the layer was known, the volume of the extrafiber fluid and the fibers was determined from their areas. The technique consisted of gently pressing the muscle between two glass plates. The thickness of the layer was controlled by plastic film spacers placed between the plates. The optimum thickness for mature mouse biceps muscle was found to be 125 μ. Measurements were carried out on muscles of different sizes, and it was found that the proportion of extrafiber fluid did not change very markedly during postembryonic growth. Investigations were also undertaken to ascertain the effects of starvation and deprivation of water. Starvation was found to increase the percentage of intrafiber water. Deprivation of water was found to result in a considerable decrease in the extrafiber fluid volume but to cause no dehydration of the fibers themselves.