The morphine concentration-response curves for 118AA (●) and 118GG (▲) sensory neurons are plotted in Figure 3E. The data points in both groups were fit to the Hill equation. The IC50 (nM), maximum current inhibition (%, ± s.e.m.) and Hill coefficient (± s.e.m.) for 118AA neurons were: 47 [19 to 115], 53 ± 2.4 [47 to 59] and 0.70 ± 0.16 [0.29 to 1.10] (95% confidence intervals are in brackets); and 260 [54 to 1250], 39 ± 2.6 [26 to 52] and 0.53 ± 0.22 [-0.004 to 1.06] for 118GG neurons, respectively. The plots show that in 118AA sensory neurons, morphine exhibited just over a 5-fold greater potency and a higher efficacy than 118GG neurons. The statistical comparison of both fits showed that they were significantly different (P < 0.0001).
