Figure 1. Increase in fluorescence intensity recorded after mixing membranes containing the nAcChoR with Dns-C6-Cho. Final concentrations were 0.4 micro Meter agonist binding sites and 2.0 micro Meter Dns-C6-Cho. The same experimental trace is shown on different time scales in A and B. (A) The time scale for diffusion-limited binding to preexisting slow desensitized nAcChoRs, which occurs over 10–20 ms. (B) The time scale for agonist-induced fast and slow desensitization.