Table 1.
Representative noncortical regions of quantitative autoradiography of μ, δ, κ, and ORL1 receptor binding in wild-type (+/+) and homozygous (−/−) A2A mutant mice brains
| Region | Bregma coordinates (mm) | [3H]ligand-specific binding (fmol/mg) | % Change in binding | |
|---|---|---|---|---|
| Wild-type (+/+) | Homozygous (−/−) | (−/−) | ||
| [3H]DAMGO binding | ||||
| Nucleus accumbens core | 1.34 | 103 ± 14.5 | 106 ± 12.7 | 2.9 |
| Endopiriform nucleus | 1.10 | 93.4 ± 6.1 | 92.4 ± 8.9 | −1.1 |
| Medial habenula nucleus | −1.70 | 132 ± 16.2 | 126 ± 16.7 | −4.5 |
| Thalamus | −1.70 | 50.1 ± 7.4 | 49.6 ± 7.2 | −1.0 |
| Basolateral amygdala | −1.70 | 108 ± 18.3 | 109 ± 13.0 | 0.9 |
| Periaqueductal gray | −3.40 | 65.1 ± 14.1 | 69.7 ± 11.5 | 7.1 |
| Superficial gray layer of superior colliculus | −3.40 | 103 ± 9.0 | 93.3 ± 16.2 | −9.4 |
| Intermediate gray layer of superior colliculus | −3.40 | 80.0 ± 9.0 | 74.6 ± 14.8 | −6.8 |
| [3H]deltorphin-1 binding | ||||
| Olfactory bulb | 4.28 | |||
| Exterior plexiform layer | 64.2 ± 4.6 | 68.3 ± 6.3 | 6.4 | |
| Interior granular layer | 148 ± 20.3 | 160.0 ± 20.1 | 8.1 | |
| Nucleus accumbens core | 1.34 | 56.3 ± 4.8 | 60.4 ± 4.5 | 7.3 |
| Caudate-putamen | 1.10 | 82.2 ± 6.2 | 93.5 ± 2.9 | 13.7 |
| Olfactory tubercle | 1.10 | 80.0 ± 6.4 | 68.8 ± 7.5 | −14.0 |
| Thalamus | −1.70 | 25.5 ± 1.8 | 24 ± 1.1 | −5.9 |
| Basolateral amygdala | −1.70 | 74.1 ± 5.0 | 75.0 ± 8.6 | 1.2 |
| Presubiculum | −4.04 | 61.6 ± 6.3 | 50.8 ± 3.1 | −17.5 |
| [3H]CI-977 binding | ||||
| Claustrum | 1.94 | 114 ± 10.2 | 119 ± 14.5 | 4.4 |
| Nucleus accumbens core | 1.34 | 35.0 ± 4.7 | 28.9 ± 2.5 | −17.4 |
| Olfactory tubercle | 1.10 | 29.2 ± 3.5 | 35.2 ± 2.8 | 20.5 |
| Dorsal endopiriform nucleus | 1.10 | 125.5 ± 7.6 | 136.2 ± 15.4 | 8.5 |
| Ventral pallidum | 0.14 | 47.7 ± 2.4 | 46.0 ± 6.2 | −3.6 |
| Basolateral amygdala | −1.70 | 37.8 ± 5.6 | 38.6 ± 3.7 | 2.1 |
| Hypothalamus | −1.70 | 35.9 ± 4.4 | 32.6 ± 1.1 | −9.1 |
| Substantia nigra | −3.40 | 37.7 ± 2.3 | 31.8 ± 2.5 | −15.6 |
| Superficial gray of the superior colliculus | −3.40 | 7.3 ± 1.8 | 8.8 ± 3.2 | 20.5 |
| [3H]nociceptin binding | ||||
| Anterior olfactory bulb | 3.08 | 88.2 ± 6.4 | 83.9 ± 5.6 | −4.9 |
| Nucleus accumbens | 1.34 | 55.4 ± 2.2 | 55.1 ± 3.1 | −0.5 |
| Thalamus | −1.70 | 39.5 ± 1.4 | 37.1 ± 1.4 | −6.1 |
| Amygdala | −1.70 | 111 ± 8.0 | 105 ± 7.9 | −5.4 |
| Hippocampus | −2.46 | 60.0 ± 3.6 | 52.8 ± 2.0 | −12.0 |
| Periaqueductal gray | −3.40 | 48.6 ± 3.5 | 48.6 ± 5.8 | 0 |
| Superficial gray layer of superior colliculus | −3.40 | 78.2 ± 6.1 | 78.4 ± 1.9 | 0.3 |
| Intermediate gray layer of superior colliculus | −3.40 | 46.4 ± 2.0 | 47.2 ± 2.0 | 1.7 |
| Presubiculum | −3.40 | 75.8 ± 1.6 | 69.4 ± 3.1 | −8.4 |
The mean specific binding (n = 4) of [3H]DAMGO, [3H]deltorphin-1, [3H]CI-977, or [3H]nociceptin (femtomoles per milligram) ± SEM in brain regions of wild-type (+/+) and homozygous (−/−) A2A receptor knock-out mice. Measurements in the regions were performed at the bregma coordinates taken from the mouse atlas of Franklin and Paxinos (1997). Regional determinates were made from both left and right sides of the sections, which were cut 300 μm apart. The labeling was performed on sections from +/+ and −/− mice in a completely paired protocol. Specific binding of [3H]DAMGO, [3H]deltorphin-1, and [3H]nociceptin was >85% in all regions. Specific binding of [3H]CI-977 was >50% in all regions. The data show only regions expressing high receptor levels and regions associated with pain processing. Analysis of all 40–50 regions in which receptor measurements were made showed that comparison of genotypes was not statistically significant for any ligand (p > 0.05; ANOVA). The percentage (%) change in binding represents the change in binding levels in −/− brains compared with +/+. A minus sign indicates a percentage decrease in binding levels.