Figure 6.

The concentration–response relationship for the effect of pentobarbitone on the mean amplitude of spontaneous epsps in hippocampal CA1 neurons (filled triangles) and the evoked calcium transients recorded from synaptic boutons (open circles). The numbers next to the data points are the number of individual experiments at each concentration. The mean amplitude of the epsps was determined by averaging 30–70 spontaneous synaptic events before, during and after exposure to anaesthetic. Note that these concentrations of pentobarbitone had no significant effect on the amplitude of the evoked action potentials (filled circles, the dotted line indicates 100% of control).