Table 4.

³⁵S-GTPγS binding in exon 11 KO, exon 1/exon 11 KO, mMOR-CHO, mDOR-CHO, and mKOR-CHO membranes.

		Brain		Spinal Cord			CHO
Peptide	WT	E11 KO	E1/E11 KO	WT	E11 KO	mMOR	mDOR	mKOR
	Max stimulation (% over basal)
DAMGO	15 ± 2	19 ± 6	−6 ± 1	11 ± 2	7 ± 4	396 ± 21	−2 ± 7	−16 ± 8
IDAPP	31 ± 3	17 ± 4*	−2 ± 2	38 ± 2	21 ± 3*	399 ± 6	42 ± 2	44 ± 3
EM1	39 ± 2	23 ± 1**	−5 ± 3	38 ± 4	44 ± 2	322 ± 19	−3 ± 1	22 ± 5
EM2	35 ± 1	24 ± 2**	1 ± 1	45 ± 3	36 ± 4	285 ± 10	−3 ± 2	7 ± 4
	EC50 (nM)
DAMGO	190 ± 8	220 ± 13	N.D.	67 ± 8	50 ± 10	9 ± 1	N.D.	N.D.
IDAPP	60 ± 9	78 ± 5	N.D.	51 ± 2	83 ± 8	17 ± 1	>500	>500
EM1	222 ± 31	17 ± 7**	N.D.	316 ± 64	330 ± 30	44 ± 8	N.D.	216 ± 48
EM2	151 ± 43	103 ± 8	N.D.	345±69	226 ± 14	10 ± 0.1	N.D.	>500

³⁵S-GTPγS binding in brain, spinal cord, and CHO cells stably expressing opioid receptors. Maximal stimulation (% increase over basal in the absence of drug) and EC₅₀ values were calculated using nonlinear regression analysis with GraphPad Prism and are presented as mean ± SEM of at least 3 replicates. ANOVA analysis of the maximal stimulation in brain was significant for each drug (See Supplemental Figure 4). Bonferroni posthoc analysis revealed that the E1/E11 KO group was significantly different from both the other groups for all drugs. The WT groups were significantly different from the E11 groups for IDAPP, EM1 and EM2, but not for DAMGO. The EC₅₀ values in the WT and the E11 KO groups were not significantly different by Student t-test for DAMGO, IDAPP or EM2, but the values for EM1 were significantly different. Comparison of maximal stimulation in spinal cord revealed a significant drop between the WT and E11 KO group for IDAPP, but not for the other drugs. No differences in EC₅₀ values were observed.

^*p<0.05,

^**p<0.01,

^***p<0.001