Table 2.

Pharmacodynamic parameters (% relaxation at 1 mg/mL, EC₅₀ values, and potency (pEC₅₀)) and SEM obtained by nonlinear regression analysis of concentration-response curve for AECal, in isolated rat trachea precontracted by acetylcholine (10 µM) and KCl (30 mM, 80 mM).

Contractant	Contraction (% of max)	EC50 (95% CI)	pEC50  ± SEM
Ach (10−5 M)	−9.67 ± 2.60	0.024 (0.019–0.031)	1.62 ± 0.07
KCl (30 mM)	29.48 ± 6.04	0.05 (0.027–0.100)	1.29 ± 0.15
KCl (80 mM)	55.47 ± 7.42	0.49 (0.151–1.596)***	−0.35 ± 0.60***

Data are expressed as the mean ± SEM of 6–8 experiments. Significantly different from control: *P < 0.05, **P < 0.01, and ***P < 0.001.