TABLE 1
FROM:
Meta-analysis of cannabinoid ligand binding affinity and receptor distribution: interspecies differences
J M McPartland, M Glass and R G Pertwee
BACK TO ARTICLETable 1. Subgroup meta-regression: effects of methodological factors upon mean affinity values
| Methodological factor a | Affinity mean (nM), standard error, sample size | Difference between means |
|---|---|---|
| Brain homogenates versus | 3.4 1.1 (n=77) | Statistical difference, P=0.0001 |
| Brain sections | 20.83.1 (n=10) | |
| Native tissues versus | 1.60.76 (n=13) | No difference, P=0.12 |
| Transfected cells | 3.20.45 (n=38) | |
| Filtration of radioligand versus | 1.00.10 (n=56) | No difference, P=0.28 |
| Centrifugation of radioligand | 0.870.10 (n=20) | |
| K d versus | 0.980.12 (n=51) | Statistical difference, P=0.0001 |
| K i | 8.21.5 (n=26) | |
|
K
i values of CP55,940 obtained using: [3H]CP55,940 [3H]SR141716A [3H]WIN55212-2 [3H]HU243 | 1.14.55 (n=14) 19.4 3.41 (n=25) (a)0.89 4.55 (n=14)1.3 7.62 (n=5) | (a)=statistical difference to all other ligands, P=0.002 |
| Brain tissue with PMSF versus | 205.8301.9 (n=30) | Statistical difference, P=0.0001 |
| Brain tissue without PMSF | 2500.9413.3 (n=16) | |
| CB1-transfected cells with PMSF versus | 196.5123.1 (n=6) | No difference, P=0.29 |
| CB1-transfected cells without PMSF | 396.4100.5 (n=9) | |
| CB2-transfected cells with PMSF versus | 477.9385.5 (n=9) | No difference, P=0.45 |
| CB2-transfected cells without PMSF | 916.1348.7 (n=11) |
Abbreviation: PMSF, phenylmethylsulphonyl fluoride.
a All meta-regressions were performed on the single ligand and receptor that provided the greatest amount of extractable data; CP55,940 at RnCB1 data were used for all methodological factors, except the three PMSF versus no PMSF meta-regressions. For the PMSF versus no PMSF analyses, the brain tissue comparison used AEA at RnCB1 data, the CB1-transfected cells used AEA at HsCB1 data and the CB2-transfected cells used AEA at HsCB2 data. Statistical significances (P-values) were calculated with Mann–Whitney U-test (Systat; Evanston, IL, USA).