Table 5.
Influence of charybdotoxin (ChTx) on relaxation, by agents that increase cAMP, of artery rings constricted with U46619, 5-HT or 5-HT in the presence of 5-HT1B receptor antagonism
| Pre-constriction |
Isoprenaline |
Rolipram |
||||
|---|---|---|---|---|---|---|
| pEC50 | Rmax | n | pEC50 | Rmax | n | |
| U46619 | 8.47 ± 0.05 | 96.4 ± 1.9 | 5 | 7.76 ± 0.06 | 90.6 ± 2.7 | 4 |
| U46619 + ChTx | 7.80 ± 0.02§ | 90.1 ± 3.9 | 5 | 7.21 ± 0.08§ | 80.7 ± 4.1 | 4 |
| 5-HT | 7.44 ± 0.08 | 50.3 ± 2.2 | 5 | 7.08 ± 0.04 | 48.9 ± 1.4 | 4 |
| 5-HT + ChTx | 7.48 ± 0.07 | 48.4 ± 1.6 | 5 | 7.13 ± 0.03 | 48.1 ± 0.9 | 4 |
| 5-HT + SB216641 | 8.39 ± 0.02* | 98.9 ± 1.0* | 5 | 7.73 ± 0.08* | 88.3 ± 3.9* | 4 |
| 5-HT + SB216641 + ChTx | 7.52 ± 0.03# | 93.6 ± 1.4* | 5 | 7.27 ± 0.11# | 81.1 ± 5.3* | 4 |
Significantly different (0.00 < P < 0.05, anova with Tukey post test)
*
from U46619
§
or 5-HT controls;
#
from 5-HT in the presence of the 5-HT1B receptor antagonist SB216641. n= number of arteries from different animals.