Computed currents in whole cell and outside-out patch mode. (A) Computed current responses to 1.0 mM GABA in the absence of desensitization, with diffusional exchange between [Cl⁻]_i and [Cl⁻] in pipette according to equations by Pusch and Neher (1988; marked P and N), Mathias et al. (1990; marked M et al.), and without any diffusional exchange (bottom curve). Cell radius, 6.2 µm. R_s between pipette and cell, as indicated. (B) Computed responses to 1.0 mM GABA with equilibration according to Mathias et al. (1990) for cell radii, r, as indicated. Note the faster decay but higher relative steady current (normalized to peak current) at smaller radius. Maximum conductance per unit area constant for all simulations. R_s as indicated. For all computations of diffusional exchange (A and B), Cl⁻ movement between cytosol and pipette as a consequence of the electric current was also included. (See supplemental text, section VIII, for equations.) Initial [Cl⁻]_i was as in the pipette solution, 5.4 mM.