Table 1.
Effect of age and estrogen treatment on the AR and BDNF mRNA expression level in song control nuclei of males
| P20–25 (n = 6)
|
P30–35 (n = 6)
|
P20–25 + E2 (n = 6)
|
||||
|---|---|---|---|---|---|---|
| AR | BDNF | AR | BDNF | AR | BDNF | |
| HVc | 35.4 ± 3.3 | 1.5 ± 0.3 | 29.0 ± 4.5 | 23.0 ± 4.2 | 27.5 ± 1.7 | 19.5 ± 3.8 |
| IMAN | 28.6 ± 2.9 | 0.9 ± 0.2 | 33.0 ± 7.1 | 1.0 ± 0.3 | 26.2 ± 4.1 | 1.2 ± 0.4 |
| RA | 8.1 ± 3.5 | 1.1 ± 0.5 | 12.5 ± 3.5 | 1.8 ± 0.7 | 9.8 ± 2.6 | 1.4 ± 0.3 |
| nXIIts | 31.0 ± 2.7 | 0.2 ± 0.1 | 35.0 ± 4.2 | 0.2 ± 0.1 | 24.3 ± 1.1 | 0.1 ± 0.1 |
| Anterior neostriatum | 1.6 ± 0.7 | 12.8 ± 1.2 | 1.0 ± 0.3 | 15.3 ± 2.8 | 0.8 ± 0.2 | 0.1 ± 0.1 |
The expression level in a brain region is indicated by the percentage (mean ± SD) of the number of labeled cells by using the 99% Poisson criterion (30) after in situ hybridization for AR or BDNF mRNA. Values around 1% or less are in the range of the expected number of false positives by using the 99% Poisson criterion. The expression level of BDNF mRNA in the HVc is significantly higher in P30–35 compared with P20–25 males and is increased significantly at P20–25 after treatment with estrogen (E2) (t test; P = 0.001). Age or estrogen treatment had no significant effect on the BDNF mRNA expression level either in IMAN and RA or in the anterior neostriatum. The expression level of AR mRNA was not affected by age or estrogen treatment in the areas investigated. nXIIts, tracheosyringeal part of the hypoglossal nucleus.