Table 3

Effect of exposure to 3 ppm O₃ for 1 h on relaxation to intraluminal NaCl in the perfused trachea

Treatment (n)	EC₅₀ (95% CI)	Maximum Response^3-b
	mM^3-a	% MCh
0 h
Air (8)	10.8	83.2 ± 8.1
	(8.9–13.2)
O₃ (8)	10.9	69.1 ± 5.5^3-c
	(8.8–13.5)
2 h
Air (5)	7.7	78.9 ± 4.7
	(5.5–10.9)
O₃(5)	11.2	62.0 ± 4.2^3-c
	(9.1–13.8)
6 h
Air (5)	6.5	85.2 ± 8.7
	(3.9–11.0)
O₃ (5)	11.7	62.6 ± 6.2^3-c
	(5.6–24.7)
12 h
Air (6)	7.5	72.0 ± 3.9
	(5.1–11.0)
O₃ (6)	7.1	68.6 ± 3.2
	(6.1–8.3)
18 h
Air (7)	5.6	66.2 ± 2.7
	(3.9–8.1)
O₃ (7)	7.4	69.2 ± 2.8
	(5.8–9.5)

↵3-a Values refer to NaCl millimolar concentration added to MKH solution.
↵3-b Relaxation responses in centimeters of H₂O normalized as a percentage of the extraluminal MCh (3 × 10⁻⁷ M)-induced contraction.
↵3-c Significantly less than air-treated controls.