Figure 4: Determination of EGABA on TC neurons.
(a) Representative traces of a GABA response are shown at different holding potentials. In order to measure the equilibrium potential of the GABA (EGABA) response, 1 mM GABA was administered with 20–30 p.s.i. pressure at a distance of 50–100 μm from the soma. To avoid disruption of [Cl−]in, a gramicidin-perforated patch recording was performed and compared with the whole-cell patch configuration (equimolar [Cl−] conditions both intracellularly and extracellularly). All recordings were performed in a bath solution containing 50 μM APV and 20 μM CNQX. (b) GABA responses at different potentials were plotted to show the I–V relationship. The intercept of the I–V curve of the perforated patch current (open circle, n=3 from three mice) indicated that EGABA of TC neurons was −72 mV, whereas EGABA of the whole-cell current (solid circle, n=8 from three mice) was 0 mV. Error bars represent mean±s.e.
