Article Figures & Data
Figures
- Fig. 1.
Perforated patch-clamp recording in a nRt cell. Shown are current responses to a 20 mV hyperpolarizing voltage step after seal formation (A) and 8 min thereafter (B). Note the increase in amplitude of the instantaneous (▪) and steady-state currents (□) because of perforation of the patch with gramicidin. Traces are averages of five sweeps.C, Time series of instantaneous current amplitudes during perforated patch formation. The calculated final access resistance was 59 MΩ in this experiment. D, Time series of the steady-state current. Note the continuous decrease from the initial values, which mainly indicate seal resistance, to the final values reflecting mainly input resistance.
- Fig. 2.
GABA-induced membrane currents at different command potentials (−100 to −50 mV) obtained with gramicidin-filled patch pipettes from a nRt neuron (A) and a relay cell (B). GABA (50 μm) was pressure-applied focally at the time point indicated by arrows. CGP 35348 (0.5 mm) was present in the extracellular solution.Insets, Current amplitudes (pre-GABA, ▪, and GABA, □) were measured at times indicated by horizontal bars. C, D, Current–voltage relationship of the leak current (pre-GABA, ▪) and the total current during GABA application (GABA, □) in the same cells as inA and B. The reversal potentials (intersections of the two I–V curves) are indicated byarrows and were −70 mV in C and −81 mV in D.
- Fig. 3.
A, B, Perforated patch-clamp recording from a relay cell before (A) and after (B) rupturing the patch in the presence of CGP 35348 (0.5 mm). GABA (50 μm) was pressure-applied focally at time points indicated byarrows. C, D, Current–voltage relationship of leak (▪) and agonist-induced (□) membrane currents in A and B. Note the dramatic increase in current amplitudes and shift of the reversal potential after establishing conventional whole-cell recordings (A vs B). The reversal potential inC was −87 mV, and the extrapolatedEGABA in D was −31 mV.
- Fig. 4.
A monosynaptically evoked IPSC recorded in a relay cell during a perforated patch-clamp experiment is shown inA at different command potentials (−100 mV to −70 mV). Excitatory synaptic transmission was blocked with CNQX and APV, and GABAB IPSCs were blocked with CGP 35348. The stimulus artifact is partially truncated for clarity. B, Current–voltage relationship of the total current during the IPSC (□) and the pre-IPSP current (▪) intersect at −81 mV, as indicated by an arrow.
- Fig. 5.
GABA-induced membrane current at different holding potentials in a relay cell in control (A) and after bath application of the chloride transport blocker furosemide (B; 1 mm). GABA (50 μm) was applied focally at time points indicated by arrows.C, D, Current–voltage relationship of leak (▪) and total (GABA + leak; □) currents in control condition (C) and after furosemide application (D). Note the shift of current cross-points (arrows) after furosemide application, indicating a depolarizing shift ofEGABA.
