COMPARISON OF THE USE OF GEL THREADS AND MICROCARRIER BEADS IN LI-SY5Y CELLS( TRANSPORT STUDIES OF HUMAN NEUROBLASTOMA SH)

We have applied Li-7 NMR spectroscopy coupled with continuous perfusio n to study Li+ transport into SH-SY5Y human neuroblastoma cells. Two m ethods commonly used in the immobilization of cells, namely entrapment in gel threads and anchorage on microcarrier beads, were used in this study. We were able to differentiate between intra- and extracellular Li-7 NMR resonances in the presence of 3 mM HTm(DOTP)(4-) as the shif t reagent, irrespective of the mode of cell immobilization. Two differ ent types of gel threads, agarose and Matrigel, were used. To determin e the optimum diameter of the threads required for this type of study, agarose threads of three different diameters were used. Our results i ndicate that agarose threads gave a first-order rate constant similar to that obtained for Biosilon microcarrier beads. The rate constant fo r Li+ influx was found to decrease with increasing thread diameter and with cells entrapped in Matrigel threads. Addition of the Li+ ionopho re DB14C4 was previously shown to increase the rate of Li+ influx into human RBCs and this effect was also observed in neuroblastoma cells w ith an increase in the pseudo-first-order rate constant of Li+ uptake by a factor of two.