Fig. 7.
The onset of the fast desensitization component is not affected by CPZ. A, Example of a current evoked by GABA pulse (1 mm for 2 msec, see inset abovethe current trace) in which single-channel activity can be observed. During the deactivation phase (after removal of GABA), the single-channel openings are separated by silent periods indicating sojourns in a desensitized state. B, C, Examples of normalized current responses to long (200 msec) GABA applications (10 mm, solid bars) in control conditions (B) and in the presence of 100 μm CPZ (C). The decaying phases, during GABA applications, were fitted with Equation 1 (Materials and Methods). Time constants are specified below the traces, and the steady-state fractions of currents (As) are 0.21 and 0.17 for control and in the presence of 100 μm CPZ, respectively.