Fig. 2. Protocols used to measure two forms of tolerance using experiments carried out in wild-type animals. (A) Snake plot illustrates the phosphorylation sites on the C terminus (yellow: T354, S355, S356, T357, S363, T370, S375, T376, T379, T383, and T394). (B) Protocol used to determine the acute desensitization and the recovery from desensitization. (C) Summary of results showing the time course of recovery from desensitization slices from untreated (black) and MTAs (red); blue dots indicate the results from the trace in (B). (D) Trace shows the current induced by morphine (1 µM, 1) relative to that induced by ME (30 µM, 2). (E) Summary of the results measuring the relative current induced by morphine (½) in slices from untreated animals (95% confidence interval, 0.518 ± 0.047) and MTAs (95% confidence level 0.37 ± 0.045), indicating that the morphine-induced current is smaller in slices from MTAs. Mann-Whitney U test P < 0.001. Blue dot indicates the results from the experiment in (D). *P < 0.05.