Table 2.
Pharmacological profiles of [3H]-NMS and [3H]-CGP12,177 binding sites in human bronchus and lung
| [3H]-NMS binding sites | [3H]-CGP-12,177 binding sites | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Pirenzepine (M1- subtype) | AF-DX 116 (M2- subtype) | Darifenacin (M3- subtype) | ICI-89,406 (β1- subtype) | ICI-118,551 (β2- subtype) | ||||||
| Region of the airway | pKihigh (%) | pKilow | pKihigh (%) | pKilow | pKihigh (%) | pKilow | pKihigh (%) | pKilow | pKihigh (%) | pKilow |
| Segmental bronchus | 7.4 ± 0.2 | 7.3 ± 0.1 (44 ± 6%) | 5.8 ± 0.2 | 8.2 ± 0.1 (55 ± 5%) | 6.6 ± 0.1 | 6.8 ± 0.2 | 8.3 ± 0.5 | |||
| Subsegmental bronchus | 6.9 ± 0.2 | 7.1 ± 0.2 (38 ± 3%) | 5.8 ± 0.2 | 8.6 ± 0.3 (62 ± 5%) | 6.8 ± 0.1 | 6.2 ± 0.8 | 8.8 ± 0.2 | |||
| Lung parenchyma | 8.5 ± 0.3 (53 ± 4%) | 5.9 ± 0.1 | 7.1 ± 0.2 (37 ± 8%) | 5.2 ± 0.2 | 7.2 ± 0.1 | 10.2 ± 0.2 (35 ± 2%) | 7.1 ± 0.1 | 9.2 ± 0.2 (66 ± 1%) | 6.8 ± 0.2 | |
Competition binding experiments with intact tissue segments were carried out at 4°C. The concentrations of [3H]-NMS and [3H]-CGP-12,177 used were 500 pM.
pKihigh and pKilow: negative logarithm of the equilibrium constants (pKi) at high and low-affinity sites for tested drugs. (%): percentage of high-affinity sites.
Data represent means ± SEM of 4–5 experiments.