Larger Image Figure 5. I–V relations of GABA-activated currents in the presence and nominal absence of extracellular Cl−. The patch was obtained using a pipette solution with 120 mM extracellular Na-MES and 0 Cl−o, whereby a 300-mM KCl “agar bridge” was used in the pipette. Outward transport current was defined by substituting 20 mM GABA for 20 mM aspartate in the presence of 120 mM NaCl on the cytoplasmic side. After replacing the cytoplasmic solution with 120 mM NMG-MES, inward current was activated with extracellular GABA in the presence of Na+o. Both were defined with a 0.4 mM GABAo subtraction. The extracellular solution in b contained 120 mM Na-MES and was Cl− free; in c the extracellular solution contained 120 mM NaCl, which was applied by pipette perfusion. The voltage steps were 35 ms in duration. Data points represent the average of current magnitudes at the specified membrane potential during the cumulative voltage protocol. Image published in: Lu CC and Hilgemann DW (1999) © 1999 The Rockefeller University Press. Creative Commons Attribution-NonCommercial-ShareAlike license Permanent Image Page Printer Friendly View XB-IMG-121030 |