Pharmacological regulation of membrane δ receptor expression Dorsal root ganglion neuron cell-surface δ receptor expression measured by flow cytometry after opioid ligand exposure. Naive neurons or neurons treated for 18 h with CTAP or TIPP were treated subsequently for 10 min with DPDPE. The mean δ receptor-PerCP fluorescence labeling intensity of the neuronal population was determined and expressed as a percentage of untreated neurons of the same genotype (± S.E.M.). Data were analyzed by ANOVA for each genotype (μ+/+, df = 5.0, F = 7.45; μOR-/-,df = 5.0, F = 6.84) followed by the least significant difference post hoc test.
| DPDPE (1 μM) | CTAP (0.3 μM) | CTAP (0.3 μM) + DPDPE (1 μM) | TIPP (5 μM) | TIPP (5 μM) + DPDPE (1 μM) | |
|---|---|---|---|---|---|
| % | |||||
| μ+/+ | 93 ± 2 | 102 ± 5 | 139 ± 5** | 128 ± 6** | 137 ± 4** |
| μ–/– | 85 ± 7 | 96 ± 4 | 102 ± 7 | 135 ± 14** | 153 ± 18** |
↵** p < 0.005 versus untreated sample of the same genotype