Peak DAMGO-evoked current responses and EC50 values for MOR wild-type and the four point mutants.
| Mean Peak Current ± S.E. | EC50 (95% C.I.) | |
|---|---|---|
| nA | nM | |
| MOR WT | 2320 ± 316 | 41.8 (19.3–90.8) |
| MOR (Y96F) | 2470 ± 331 | 17.4 (8.79–34.5) |
| MOR (Y106F) | 2820 ± 243 | 30.0 (19.9–45.2) |
| MOR (Y166F) | 2620 ± 308 | 97.3 (56.2–168) |
| MOR (Y336F) | 2520 ± 377 | 169 (89.5–321) |
Oocytes injected with cRNA for MOR and KIR3.1 and KIR3.2 were superfused with concentrations of DAMGO ranging from 1 nM to 3 μM and used in two-electrode voltage-clamp recordings as described under Materials and Methods. Mean peak currents (3 μM DAMGO) represent n = 11 to 17 oocytes; EC50 values were generated from 11 to 18 independent dose-response curves, then averaged to produce the mean EC50value and 95% confidence interval (C.I.). Lack of significant difference between EC50 values of DAMGO for the receptors was determined by comparing generated EC50 values of MOR wild-type with each individual set of point mutant values with Student's unpaired t test, with p > 0.1 in each case.