Maintenance of the Ionic Composition of the Incubated Artery

Abstract

The ionic composition of the incubated rat tail artery, comparable but not identical to that of the freshly dissected tissue, can be maintained over a period of at least 5 h under aerobic conditions in the absence of utilizable exogenous substrate. A sufficient supply of exogenous glucose must be provided for the maintenance of this ionic composition under anaerobic conditions. The changes in the content of individual ions and water brought about by iodoacetate poisoning can be prevented more or less completely by addition of a utilizable noncarbohydrate substrate such as pyruvate or butyrate to the incubation medium. Abolition of the transmembrane ionic gradients caused by 2,4-dinitrophenol or oligomycin can be partially-prevented by exogenous glucose. The ionic composition of the artery is little affected by fluoroacetate inhibition even in the absence of utilizable exogenous substrate. The content of magnesium is decreased by 2-deoxy-D-glucose, although the content of other ions remains unchanged. Metabolic energy seems to be required to prevent the tissue calcium from rising.