. 2019 Dec 5;176(23):4510–4520. doi: 10.1111/bph.14810

Table 3.

Effects of fentanyl and naloxone on cAMP content

Effect	Parameter	MOR‐WT	MOR‐WT	MOR‐WT	MOR‐H297A
Effect	Parameter	pH 7.4	pH 6.5	pH 6.0	pH 7.4
Fentanyl‐induced cAMP reduction	IC₅₀ (nM) [95% CI] log (IC₅₀)	1.3 [0.7, 2.4] −8.90 ± 0.14	1.4 [0.5, 4.0] −8.71 ± 0.33	1.8 [0.4, 8.6] −8.74 ± 0.34	33.4 [5.6, 198.6] −7.48 ± 0.40*
Fentanyl‐induced cAMP reduction	Bottom (%)	28.8 ± 2.1	33.2 ± 2.9	39.5 ± 4.0	53.3 ± 4.7*
Naloxone antagonism of fentanyl‐induced cAMP reduction	IC₅₀ (μM) [95% CI] log (IC₅₀)	14.4 [5.8, 35.9] −4.84 ± 0.20	2.6 [0.9, 7.7] −5.58 ± 0.25*	18.7 [7.6, 45.6] −4.73 ± 0.20
Naloxone antagonism of fentanyl‐induced cAMP reduction	Top (%)	93.1 ± 5.7	58.7 ± 3.4*	106.3 ± 6.3

Note. Data are means ± SEM or means with 95% CI. Bottom: bottom of curve fit (maximum fentanyl effect); Top: top of curve fit (maximum reversal of fentanyl effect); log (IC₅₀), Bottom and Top were each compared by one‐way ANOVA with Dunnett's Multiple Comparison post hoc test, control group = MOR‐WT pH 7.4.

P < 0.05, n = 6 per experiment.