Fig. 5. Stereoselective effects of the thiopental enantiomers on inhibitory γ-aminobutyric acid–mediated (GABAergic) currents. (A ) Representative traces showing the effects of 10 μm S(−) and R(+) thiopental on GABAergic synaptic currents. The S(−) enantiomer (circles) is significantly more effective than the R(+) enantiomer (squares) at prolonging the postsynaptic current decay (in this example, the decay half-times differ by approximately 2.4-fold). (B ) The amplitude of the inhibitory postsynaptic current (IPSC) was not significantly affected by either enantiomer. (C ) The increase in total charge transfer (the total area under the IPSC) is plotted as a percentage change from the control value for each of the enantiomers. The points represent mean values (for an average of 10 cells). In all cases the lines are drawn by eye and have no theoretical significance.