Specific-to-Nonspecific 123I-FP-CIT Binding Ratios, Obtained 1 and 3 Hours After Injection of Radiotracer, in DAT-Rich Brain Area (Striatum) and in SERT-Rich Areas (Midbrain and Diencephalon)
| 1 h after injection | 3 h after injection | |||
|---|---|---|---|---|
| 123I-FP-CIT Binding | Placebo | Paroxetine* | Placebo | Paroxetine |
| DAT | ||||
| Striatum/cer.† | 2.30 ± 0.80 | 2.10 ± 0.27 | 3.95 ± 0.36 | 3.71 ± 0.55 |
| Striatum/occ. | 2.95 ± 0.97 | 2.93 ± 0.44 | 3.97 ± 0.15 | 4.41 ± 0.43‡ |
| SERT | ||||
| Midbrain/cer. | 0.13 ± 0.12 | −0.04 ± 0.14‡ | 0.21 ± 0.14 | −0.04 ± 0.05‡ |
| Midbrain/occ. | 0.35 ± 0.10 | 0.22 ± 0.17‡ | 0.21 ± 0.12 | 0.10 ± 0.06 |
| Diencephalon/cer. | 0.29 ± 0.16 | 0.08 ± 0.13§ | 0.51 ± 0.17 | 0.17 ± 0.15‡ |
| Diencephalon/occ. | 0.54 ± 0.15 | 0.38 ± 0.20§ | 0.51 ± 0.10 | 0.34 ± 0.13‡ |
↵* Placebo or paroxetine tablets (20 mg per session) were taken orally approximately 3 and 27 h before injection of radiotracer.
↵† Ratios are expressed as specific to nonspecific binding (±SD). Nonspecific binding represents activity in cerebellum (cer.) or occipital cortex (occ.).
↵‡ Statistically significantly different from placebo condition.
↵§ A trend for statistically significant difference (P = 0.07−0.09).
Healthy control subjects (n = 5) received placebo or paroxetine before injection of radiotracer (double-blind, crossover study design). In these 5 control subjects, at the paroxetine session, paroxetine plasma levels were >5 μg/L, whereas at the placebo session, paroxetine was not detectable in plasma (<5 μg/L).