Measurement of cromakalim-induced 87Rb flux in intact cells by NMR

Abstract

87Rb nuclear magnetic resonance signals from intracellular and extracellular Rb + can be distinguished by the use of shift reagents, thus permitting the simultaneous measurement of intracellular and extracellular Rb concentrations. When smooth muscle cells are suspended in a medium containing Rb + in place of K +, there is a slow influx of Rb +, which is greatly increased by the addition of cromakalim to the medium. The concentration of cromakalim required to stimulate influx is similar to that needed to stimulate 86Rb efflux from isolated tissue.