Table 4.
Influence of charybdotoxin (ChTx) on relaxation, by agents that increase cGMP, of artery rings constricted with U46619, 5-HT or 5-HT in the presence of 5-HT1B receptor antagonism
| Pre-constriction |
Bradykinin |
SNP |
Zaprinast |
||||||
|---|---|---|---|---|---|---|---|---|---|
| pEC50 | Rmax | n | pEC50 | Rmax | n | pEC50 | Rmax | n | |
| U46619 | 7.83 ± 0.11 | 100 ± 4.4 | 5 | 7.78 ± 0.10 | 100 ±1.6 | 5 | 7.43 ± 0.11 | 100 ± 5.6 | 4 |
| U46619 + ChTx | 7.15 ± 0.10* | 52.8 ± 0.1* | 5 | 7.01 ± 0.04* | 51.0 ± 0.6* | 5 | 6.65 ± 0.18* | 58.4 ± 6.9* | 4 |
| 5-HT | 7.66 ± 0.06 | 51.7 ± 1.6 | 5 | 7.45 ± 0.06 | 51.2 ± 1.7 | 5 | 7.10 ± 0.15 | 48.1 ± 3.9 | 4 |
| 5-HT + ChTx | 7.40 ± 0.11 | 52.0 ± 2.6 | 5 | 7.40 ± 0.06 | 47.3 ± 1.8 | 5 | 7.02 ± 0.11 | 50.7 ± 3.1 | 4 |
| 5-HT + SB216641 | 8.42 ± 0.05* | 88.8 ± 1.8* | 5 | 8.16 ± 0.05* | 91.4 ± 2.0* | 5 | 7.55 ± 0.08 | 97.4 ± 3.8* | 4 |
| 5-HT + SB216641 + ChTx | 7.53 ± 0.06# | 51.5 ± 1.3# | 5 | 7.35 ± 0.08# | 51.8 ± 2.6# | 5 | 6.94 ± 0.16# | 53.6 ± 5.1# | 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.