DAMGO and DELT can interact additively or synergistically in the nucleus raphe magnus to produce antinociception
Values are the dose and 95% CL to increase paw withdrawal latency to 14 s. For the fixed dose mixtures, the values are the total dose in mass units of both drugs microinjected concurrently. Thus, for a 1:1 mixture, microinjection of 0.1 ng of DAMGO and 0.1 ng of DELT corresponds to a total dose of 0.2 ng. Theoretical additive values and estimate of the variance were calculated as described by Tallarida (2000).
Drug | ED50 | 95% CL | |
|---|---|---|---|
| ng | |||
| DELT | Alone | 1318.6 | (1037.5-2971.7) |
| DAMGO | Alone | 3.6 | (1.9-7.7) |
| 1:273 DAMGO:DELT | Additive | 562.6 | (328.8-796.4) |
| 1:273 DAMGO:DELT | Experimental | 333.0 | (175.8-739.6) |
| 1:1 DAMGO:DELT | Additive | 7.1 | (2.3-12.0) |
| 1:1 DAMGO:DELT | Experimental | 0.4** | (0.2-0.8) |
| 10:1 DAMGO:DELT | Additive | 3.9 | (1.3-6.6) |
| 10:1 DAMGO:DELT | Experimental | 0.2* | (0.008-1.2) |
↵* p < 0.05, ** p < 0.01 compared with the theoretical additive value for that fixed dose ratio.