Action of pretreatments changes in potency (Δ–log EC50) of endothelin-1 (ET-1) in human isolated bronchi.

Values were determined in paired human bronchi after incubation with 0.1 µM fenoterol or oxygenated Krebs–Henseleit solution (control) for 15 hours at 37°C with or without pretreatment co-incubated with fenoterol (Fig 56). ET-1 potency (−log EC50) was derived graphically from the log concentration-effect curves and defined as the negative log of the ET-1 concentration achieving 50% of the maximal effect. Δ(−log EC50) represents the difference between −log EC50 obtained with the fenoterol-treated bronchi and −log EC50 obtained with their paired controls. The observed effect of pretreatment co-incubated with fenoterol is small (|d|≥.20), medium (|d|≥.50), or large (|d|≥.80) according to the Cohen's conventions [36]. The 95% CI for d consists of the uncertainty around the real effect of pretreatment. Except for wortmaninn which was added in organ bath before concentration-response curve for ET-1. *P<.05, **P<.01, ***P<.001 with vs without pretreatment.

Action of pretreatments changes in potency (Δ–log EC50) of endothelin-1 (ET-1) in human isolated bronchi.