The uptake of ions and neutral solutes by the artery and by artery wall preparations

Radiotracer methods have been used to measure the distributions of inorganic ions in the aorta. Data on fresh tissue were generally consistent with previous measurements and showed UCa greater than UI greater than UNa. In order to relate these measurements to the macromolecular composition of the arterial wall, the effects of various interventions--cell lysis, autoclaving, and NaOH digestion--were investigated. Elastin was found to be the major determinant of ionic distribution coefficients, to possess a slight positive charge under physiological conditions, and to display a high affinity for Ca++. The distribution coefficients did not conform to the predictions of the Donnan theory of ionic equilibrium and the degree of nonideality, as measured by the fixed charge density and the ion selectivity coefficients, varied with ionic strength. Data are also presented on the distribution of neutral solutes of different molecular weights in the various arterial preparation, in order to provide a basis for comparison of the behaviour of charged solutes.