Fig. 3.
Determining the functional stoichiometry of AMPA receptor desensitization. a, Schematic of the cooperative dimer model. b, GluR-A experimental records (dots; patch number 010123p1) fit with the concerted/independent models (left, solid line) and the cooperative dimer model (right,solid line). The first 25 msec of four test responses [time after conditioning response (tc) was 8, 40, 60, and 105 msec] were superimposed for comparison. The dashedline indicates zero current level. c, Plot profiling the distribution of each state in the cooperative dimer model at a range of interpulse intervals. d, Summary plots showing how fits of experimental data with different models of desensitization were compared. Fits were compared pairwise, using theF ratio test. Top plot shows the independent dimer compared with the concerted/independent models.Middle plot compares the cooperative dimer with concerted/independent models and independent dimer model. Bottom plot compares the tetramer model with all other models of desensitization. Each bar indicates the confidence level distinguishing between two models fit to the same experimental data. For every comparison six bars are shown that represent the results from six separate patch recordings. The dashed line in each plot denotes the 95% confidence level.