Summary of Schild plot results for ibodutant against NKA and the selective NK2 receptor agonist LMN-NKA in human colonic circular smooth muscle
pA2 values and slopes were generated from Schild plot and expressed as means ± S.E.M. All slopes were not significantly different from 1, and there was no difference between the slopes. Values in parentheses are the mean apparent pKB of individual ibodutant concentrations calculated using the equation pKB = log (dose ratio − 1) − log [B], where [B] is the antagonist concentration (Arunlakshana and Schild, 1959; Kenakin, 2009).
| Parameters | Ibodutant against NKA | Ibodutant against LMN-NKA | ||
|---|---|---|---|---|
| Female | Male | Female | Male | |
| pA2 ± S.E.M. (apparent pKB) | 8.36 ± 0.38* (8.22 ± 0.17)** | 7.26 ± 0.21 (7.10 ± 0.14) | 8.14 ± 0.36 (7.99 ± 0.19) | 8.33 ± 0.22* (8.11 ± 0.08)** |
| Schild slope ± S.E.M. | 0.76 ± 0.14 | 0.81 ± 0.055 | 0.72 ± 0.17 | 0.90 ± 0.12 |
| Slope different from 1 | No | No | No | No |
| P = 0.24 | P = 0.077 | P = 0.24 | P = 0.51 | |
↵* P < 0.05; **P < 0.01, compared with male against NKA (one-way ANOVA with Bonferroni’s test).