Table 1.
Concentration (ng/g brain tissue) of neurotransmitters and related metabolites in brain tissue (n = 7–8)
| Age at administration | PND 2–5 | PND 7–10 | PND 17–20 | |||
|---|---|---|---|---|---|---|
| Vehicle | TiO2 NP | Vehicle | TiO2 NP | Vehicle | TiO2 NP | |
| Male | ||||||
| DA2 | 483 ± 29.71 | 529 ± 34.4*3 | 507 ± 57.6 | 530 ± 44.0 | 493 ± 43.6 | 423 ± 57.1 |
| DOPAC | 129 ± 11.3 | 134 ± 11.2 | 111 ± 12.0 | 149 ± 12.8*** | 122 ± 14.3 | 111 ± 17.9 |
| HVA | 147 ± 15.3 | 147 ± 23.5 | 205 ± 48.1 | 154 ± 13.6* | 288 ± 100 | 159 ± 47.9* |
| NE | 247 ± 18.6 | 251 ± 38.4 | 242 ± 29.8 | 257 ± 34.9 | 235 ± 34.1 | 198 ± 56.6 |
| 5-HT | 238 ± 57.0 | 239 ± 60.2 | 239 ± 47.3 | 283 ± 28.8 | 274 ± 52.6 | 276 ± 36.1 |
| 5-HIAA | 463 ± 155 | 489 ± 71.4 | 471 ± 124 | 458 ± 19.4 | 420 ± 50.7 | 487 ± 78.4 |
| Female | ||||||
| DA | 485 ± 28.4 | 544 ± 41.1*** | 495 ± 30.2 | 549 ± 39.1*** | 508 ± 37.8 | 466 ± 78.3 |
| DOPAC | 127 ± 9.71 | 135 ± 13.5 | 116 ± 8.71 | 149 ± 24.5* | 123 ± 7.04 | 127 ± 26.2 |
| HVA | 143 ± 12.0 | 147 ± 23.5 | 207 ± 16.2 | 154 ± 13.4*** | 266 ± 94.4 | 172 ± 37.8** |
| NE | 264 ± 40.2 | 255 ± 37.1 | 239 ± 33.8 | 264 ± 29.7 | 305 ± 26.0 | 186 ± 44.5*** |
| 5-HT | 242 ± 46.0 | 310 ± 68.6 | 249 ± 48.7 | 284 ± 27.2 | 317 ± 41.2 | 261 ± 46.5 |
| 5-HIAA | 498 ± 58.4 | 516 ± 74.9 | 530 ± 79.9 | 442 ± 61.7 | 443 ± 42.9 | 477 ± 47.1 |
1Data is presented as median ± standard deviation
2Dopamine (DA), dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), norepinephrine (NE) (also called noradrenaline (NA) or noradrenalin), serotonin (5-HT), and 5-hydroxyindole-3-acetic acid (5-HIAA)
3Significant differences in concentrations between TiO2 NP and the corresponding vehicle control is indicated: *P < 0.05, **P < 0.01, and ***P < 0.005