Table 2.
Antagonism of rauwolscine or phentolamine against the inhibitory effects of UK-14,304 on cholinergic contractions
| pKd (ileum) | pKd (colon) | |
| Vehicle | ||
| Rauwolscine 1 μM | 7.61 (7.20–8.02) | 7.73 (7.44–8.02) |
| Phentolamine 1 μM | 8.94 (8.61–9.27) | 9.06 (8.64–9.48) |
| DNBS | ||
| Rauwolscine 1 μM | 7.55 (7.23–7.87) | 7.68 (6.87–8.05) |
| Phentolamine 1 μM | 9.13 (8.75–9.51) | 9.24 (8.89–9.59) |
Ileal and colonic preparations were obtained from rats either in the absence or in the presence of DNBS-induced colitis. The cholinergic contractile activity of longitudinal muscle was evoked by electrical transmural stimulation of intestinal tissues (0.5 ms, 5 Hz, 30 mA, 25 pulses every 60 s). Values reported for pKd, with 95% CI in brackets, were determined from the rauwolscine- or phentolamine-induced shift of the concentration-response curves (n=6 for each point) of UK-14,304 at the level of EC50.