Table 2.
Maximum G-protein efficacy (Emax ± SEM) and potency (EC50 ± SEM) of 14-O-MeM6SU, compared to morphine and fentanyl in vehicle (non-diabetic) and 9 and 12 weeks STZ (diabetic) treated rat brain performed in [35S]GTPγS binding assays.
| Emax ± SEM (%) | EC50 ± SEM (nM) | |||
|---|---|---|---|---|
| Non-diabetic | Diabetic | Non-diabetic | Diabetic | |
| 9 weeks | ||||
| 14-O-MeM6SU | 145.7 ± 2.4### (n = 6) | 140.7 ± 2.1 (n = 6) | 29.51 ± 11.44 (n = 6) | 33.19 ± 19.09 (n = 6) |
| Fentanyl | 140.2 ± 2.67## (n = 7) | 134.8 ± 2.84 (n = 5) | 36.64 ± 18.42 (n = 7) | 32.02 ± 20.14 (n = 5) |
| Morphine | 128.8 ± 2.65 (n = 7) | 133.5 ± 4.85 (n = 6) | N.D.1 | N.D.1 |
| 12 weeks | ||||
| 14-O-MeM6SU | 148.5 ± 3.59## (n = 4) | 146.1 ± 3.22# (n = 5) | 34.99 ± 17.74 (n = 4) | 27.86 ± 13.87 (n = 5) |
| Fentanyl | 149.7 ± 2.38## (n = 5) | 146.1 ± 3.51# (n = 4) | 197.7 ± 54.05+ (n = 5) | 124.74 ± 55.64 (n = 4) |
| Morphine | 135.2 ± 2.65 (n = 4) | 135.6 ± 3.08 (n = 4) | N.D.1 | N.D.1 |
Values were calculated according to Figure 9. #Indicates the significant difference compared to morphine within control or diabetic samples (#P < 0.05; ##P < 0.01; ###P < 0.001). +indicates the significant difference compared to 14-O-MeM6SU within control or diabetic samples (+P < 0.05). 1Not determined, since the EC50 values could not be interpreted. Two-way ANOVA followed by Fisher’s LSD post hoc test.