Figure 10.

PDP was independent of intracellular Cl⁻ accumulation. A, GABA currents measured every 30 s before and after depolarization to +40 mV. At t = 0, GABA was coapplied to the depolarized neuron in a low extracellular [Cl⁻] bath solution (Na-methanesulfonate substitution for NaCl, [Cl⁻]_o = 3 mm). The net charge movement induced by GABA in low [Cl⁻] solution was −2.37 nC, indicating a net outward Cl⁻ flux. PDP was still seen despite this reduction in intracellular Cl⁻ concentration. No baseline adjustment was made to the displayed records. B, Mean normalized current from seven experiments as in A (open circles). The filled circle represents the mean PDP produced by transient depolarization alone without GABA application. The solid line is a single exponential function. Error bars represent SEM.