4-acetamido-4--isothiocyanatostilbene-2-2--disulfonic-acid and Spinal-Cord-Neoplasms

Cl- transport was studied in the glioma cell line LRM55 . Our results indicate that LRM55 cells contain two major Cl- transporters, an anion exchanger and a K+/Cl- cotransporter , and that these are similar to the Cl- porters found in primary cultures of astrocytes. The exchanger was studied by measuring fluxes of Cl- (as 36Cl-). 36Cl- flux was trans-stimulated by Cl- or HCO-3 and was inhibited by SITS or furosemide. The K+/Cl- cotransporter was studied by measuring fluxes of 36Cl- and K+ (as 86Rb+). External K+ stimulated 36Cl- influx, and external Cl- stimulated 86Rb+ influx. Furosemide, but not SITS, inhibited the K+/Cl- cotransporter . As in primary cultures of astrocytes, the steady-state concentration of Cl- in LRM55 cells was higher than that predicted from passive equilibration according to the membrane potential. LRM55 cells appear to be a good in vitro model for glial Cl- transport.

Topics: 4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid; Animals; Astrocytes; Bicarbonates; Cell Line; Chlorides; Furosemide; Glioma; Ion Channels; Kinetics; Membrane Potentials; Potassium; Rats; Sodium; Spinal Cord Neoplasms; Temperature

SITS, an inhibitor of anion exchange, was found to be a potent and selective inhibitor of L-glutamic acid uptake by cultured LRM55 glioma cells and rat brain astrocytes. Synaptosomal uptake of glutamate was relatively insensitive to inhibition by SITS. This differential effect indicates that the glutamate transport system in glia differs from that in neurons and that SITS may provide a tool for investigating the exclusive neuronal transport and metabolism of L-glutamic acid.

Topics: 4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid; Animals; Astrocytes; Brain; Cell Line; Glioma; Kinetics; Neoplasms, Experimental; Neuroglia; Neurons; Rats; Rats, Inbred Strains; Spinal Cord Neoplasms; Stilbenes; Synaptosomes