Fig. 5.

Macroscopic desensitization during a long GABA pulse. A, macroscopic current responses to a 500-ms pulse of saturating GABA (indicated by black bar above traces). Each mutant response is overlaid with the normalized wild-type response (light gray lines). B and C, macroscopic currents for all receptor types were fit with a biexponential equation, although several responses for R120A and R120A/D163A required only a monoexponential equation during fits. B, summary of weighted time constants for desensitization. C, summary of the extent of desensitization after 500 ms. *, significant differences (P < 0.05) between control and mutant values were calculated using ANOVA with a Dunnett's post test.