Effect of Tissue Size on Measurements of Sodium, Potassium and Water Contents of Isolated Rat Ventricular Tissue

Abstract

DURING the course of experiments designed to examine the effects of inhalation anaesthetics on the sodium, potassium and water contents of isolated rat atrial tissue¹, it was noted that the standard deviations of the sodium values were rather high. These values were thought to be unreliable and were therefore not reported. It was felt that part of the deviations in sodium values could be explained by the fact that uniform blotting procedures were not used on all tissues, thus removing variable quantities of sodium-rich bathing medium. Part of the difference could also be explained on the basis of contamination of the tissue or its digest from any number of sources, despite diligent care to use demineralized water and clean apparatus. Since the tissue was so small (about 50 mg) and its sodium content so small, it is easy to see that the slightest contamination would give erroneous results. As the experiments progressed, however, and greater attention was directed to the possibilities of contamination, the sodium values decreased and the standard deviations also decreased.