CB1 receptor density and agonist-stimulated [35S]GTPγS binding in rat prefrontal cortex and cerebellum after long-term treatment with fluoxetine and/or WAY100635
The Emax and pEC50 values correspond to the estimated maximal effect and half-maximal effect of the cannabinoid agonist WIN55,212-2 in [35S]GTPγS binding assays. Values are means ± S.E.M. of two independent experiments performed in brain samples from eight to nine animals for each condition.
| Vehicle | Fluoxetine | Fluoxetine + WAY100635 | WAY100635 | |
|---|---|---|---|---|
| Prefrontal cortex | ||||
| [3H]CP55,940 binding | ||||
| Bmax (fmol/mg protein) | 580 ± 41 | 524 ± 37 | 463 ± 36 | 486 ± 37 |
| pKd | 9.6 ± 0.06 | 9.6 ± 0.04 | 9.7 ± 0.05 | 9.6 ± 0.01 |
| [35S]GTPγS binding | ||||
| Emax (%) | 140 ± 3.4 | 139 ± 2.8 | 144 ± 5.6 | 138 ± 6.7 |
| pEC50 | 5.7 ± 0.25 | 5.7 ± 0.16 | 5.7 ± 0.25 | 5.8 ± 0.28 |
| Cerebellum | ||||
| [3H]CP55,940 binding | ||||
| Bmax (fmol/mg protein) | 2021 ± 184 | 1750 ± 132 | 2115 ± 154 | 1470 ± 118 |
| pKd | 9.1 ± 0.2 | 9.2 ± 0.1 | 9.1 ± 0.1 | 9.4 ± 0.2 |
| [35S]GTPγS binding | ||||
| Emax (%) | 530 ± 70 | 579 ± 39 | 656 ± 27 | 737 ± 70 |
| pEC50 | 4.9 ± 0.1 | 4.9 ± 0.2 | 5.0 ± 0.3 | 4.98 ± 0.1 |
Bmax, estimated maximal [3H]CP55,940 binding sites; pKd, estimated dissociation constants normalized as −logKd.