Table 2

Apparent pA₂ values for NTX in antinociception

Agonists	Slope Unconstrained^2-a		Constrained^2-b
Agonists	pA₂(95% CL)	Slope (95% CL)	pA₂ (95% CL)
Alfentanil	8.54 (8.46–8.61)	−1.1 (1.2–1.0)	8.66 (8.47–8.85)
EKC	7.96 (7.62–8.30)	−1.0 (1.3–0.8)	7.97 (7.93–8.01)
U69,593	7.73 (7.34–8.12)	−0.9 (1.2–0.6)	7.64 (7.49–7.79)
U50,488	7.56 (7.28–7.86)	−1.0 (1.2–0.8)	7.55 (7.42–7.67)
Bremazocine	6.94 (6.65–7.22)	−1.0 (1.3–0.7)	6.92 (6.73–7.12)
Enadoline	6.87 (6.63–7.11)	−1.0 (1.1–0.9)	6.87 (6.69–7.05)

↵2-a pA₂ values were the mean of pA₂ values (n = 4) determined by individual Schilid plots based on procedure 15 in Tallarida and Murray (1987).
↵2-b pA₂ values obtained when slopes were constrained to −1 based on procedure 17 in Tallarida and Murray (1987).