Figure 4. Dose–response relationship for currents triggered by GABA.

A, slope conductance in response to a series of voltage ramps between −90 and −40 mV measured in a cell in standard whole-cell recording mode. Different GABA concentrations were applied as indicated. B, mean slope conductance of five ramps at each GABA concentration was calculated and the mean of the control conductances measured before and after each test application was subtracted. Data were normalized to the 10 mm GABA response, measured on the same patch. The number of cells is indicated next to the data points. Data were fitted with a Hill equation, with an EC₅₀ of 0.06 mm, and a Hill coefficient of 0.8.