Table 3.
pEC50 and Emax values of 5-HT3 receptor agonists in the rat and mouse intestinal tract in the presence of methysergide (1 μM) and GR125487 (0.1 μM)
| Rat regions | mCPBa | 5-HT | 2m5-HT | 1-PBG |
|---|---|---|---|---|
|
Jejunum |
|
|
|
|
| pEC50 |
7.42±0.25 |
6.86±0.28 |
6.48±0.54 |
6.08±0.31 |
| Emax |
20.07±1.52 |
24.5±1.9 |
24.3±7.78 |
38.29±9.03 |
| |
|
|
|
|
|
Ileum |
|
|
|
|
| pEC50 |
7.07±0.17 |
6.47±0.39 |
6.07±0.68 |
6.28±0.42 |
| Emax |
16.1±1.05 |
14.0±1.1 |
12.35±4.94 |
18.1±4.37 |
| |
|
|
|
|
|
Proximal colon |
|
|
|
|
| pEC50 |
7.47±0.27 |
6.99±0.08 |
7.27±0.22 |
7.33±0.23 |
| Emax |
36.79±3.42 |
41.57±1.85 |
29.19±2.63 |
33.01±2.79 |
| |
|
|
|
|
|
Distal colon |
|
|
|
|
| pEC50 |
7.45±0.37 |
6.85±0.05 |
5.86±0.40 |
6.46±0.23 |
| Emax |
25.73±2.24 |
36.38±0.99 |
35.35±7.91 |
35.05±4.59 |
| |
|
|
|
|
| Mouse regions |
|
|
|
|
|
Jejunum |
|
|
|
|
| pEC50 |
6.29±0.32 |
6.16±0.07 |
5.98±0.15 |
5.67±0.19 |
| Emax |
44.0±2.12 |
43.86±1.96 |
54.74±3.93 |
58.42±9.81 |
| |
|
|
|
|
|
Ileum |
|
|
|
|
| pEC50 |
6.19±0.07 |
5.94±0.08 |
5.69±0.19 |
5.67±0.17 |
| Emax |
49.16±2.25 |
56.64±2.94 |
52.76±9.79 |
51.30±7.35 |
| |
|
|
|
|
|
Proximal colon |
|
|
|
|
| pEC50 |
6.34±0.10 |
6.05±0.07 |
5.57±0.17 |
5.34±0.06 |
| Emax |
21.35±2.06 |
44.94±2.25 |
22.64±3.07 |
38.94±3.43 |
| |
|
|
|
|
|
Distal colon |
|
|
|
|
| pEC50 |
6.49±0.14 |
6.22±0.16 |
5.93±0.09 |
5.87±0.10 |
| Emax | 43.46±3.61 | 39.55±3.01 | 29.31±2.57 | 46.1±3.85 |
a
Data are presented as mean±s.e.m. (n=10). pEC50 values are expressed relative to individual maxima and Emax relative to 1 μM ACh (100%).