Table 1.
Basal concentrations of dopamine (DA), noradrenaline (NA), 5-HT, and the metabolites DOPAC and HVA in the prefrontal cortex of vehicle- and EGb 761-treated rats
| 1.Analytical method: HPLC with electrochemical detection | ||||
|---|---|---|---|---|
| Treatment (EGb 761) | Basal concentrations (fmol in 10 µL, i.e. 10−10 M) | |||
| Dose (mg·kg−1) | Dosing schedule | DA | DOPAC | HVA |
| Vehicle | Once | 6.19 ± 0.39 | 987.7 ± 69.9 | 1489.2 ± 92.4 |
| 100 | Once | 5.92 ± 0.60 | 1091.3 ± 79.7 | 1527.3 ± 105.5 |
| Vehicle | Daily, 14 days | 5.84 ± 0.47 | 1022.2 ± 59.1 | 1662.3 ± 86.2 |
| 30 | Daily, 14 days | 5.63 ± 0.50 | – | – |
| 100 | Daily, 14 days | 6.55 ± 0.48 | – | – |
| 300 | Daily, 14 days | 7.61 ± 0.59 | 1280.0 ± 96.9 | 1784.4 ± 102.1 |
| Treatment (constituents) | ||||
| Vehicle | Daily, 14 days | 4.54 ± 0.53 | – | – |
| Ginkgolides | Daily, 14 days | 4.33 ± 0.41 | – | – |
| Bilobalide | Daily, 14 days | 4.71 ± 0.53 | – | – |
| Flavonoids | Daily, 14 days | 4.34 ± 0.59 | – | – |
| 2.Analytical method: HPLC with fluorescence detection | ||||
| Treatment (EGb 761) | DA | NA | 5-HT | |
| Vehicle | Daily, 14 days | 4.24 ± 0.42 | 3.41 ± 0.51 | 3.24 ± 0.63 |
| 100 | Daily, 14 days | 5.13 ± 0.46 | 4.01 ± 0.54 | 3.41 ± 0.62 |
The concentrations are expressed as mean ± SEM, n= 5 rats, where the basal value for each rat was calculated as the mean of four microdialysis samples collected at −60 to 0 min before the drug or vehicle administration. The basal levels of monoamines and metabolites did not significantly differ between the respective treated groups and analytical methods used.
DOPAC, 3,4-dihydroxyphenylacetic acid; HVA, homovanillic acid.