Abstract
1. Extracellular Ca and EDTA concentrations in arterial smooth muscle in Ca-free solutions with and without EDTA were estimated from 45Ca and [14C]EDTA washout studies. Ca concentrations were calculated from the measured rate of 45Ca washout at a given moment, combined with separate determinations of the coefficient of diffusion of Ca in the tissue, while EDTA concentrations were calculated by analysing an exponential phase of [14C]EDTA washout and checked by separate determinations of coefficient of diffusion of EDTA in the tissue.