Fig. 7.

External ions regulate the functional stoichiometry of kainate receptor desensitization. a, Typical GluR6 test responses recorded in 55 mm NaCl solutions exhibited similar decay kinetics (patch number 000724p2).b, When the first six test responses froma were aligned for comparison, the decay kinetics was revealed to be almost identical. c, Recovery from GluR6 desensitization in 55 (filled circles) and 150 (open circles) mm NaCl solutions. GluR6 recovery in 55 mm NaCl was monoexponential, where τ_rec was 1.88 ± 0.02 sec (n = 5), whereas recovery in 150 mm NaCl was not monoexponential, particularly at brief interpulse intervals (arrow; τ_rec = 3.48 ± 0.09 sec;n = 20). d, A closer examination of the plots in c shows that GluR6 responses in 55 mm NaCl recovered monoexponentially even at brief interpulse intervals, whereas responses in 150 mm NaCl clearly deviated from first-order behavior. e, Summary showing three plots in which the goodness of fit of the experimental data with different models of desensitization was compared. Goodness of fit was compared pairwise, using the F ratio test. Thefilled (n = 5) and open horizontal bars (n = 4) refer to experiments performed in symmetrical solutions of 55 and 150 mm NaCl, respectively. The dashed vertical line in each plot denotes the 95% confidence level.