TABLE 2.

Statistical analyses of dose-effect curves for cocaine or substitution of various compounds for cocaine compared with saline availability as shown in Fig. 2 and 4.

Comparisons were made in rates of responses on the active lever maintained during each corresponding component using a two-way repeated-measures ANOVA followed by post hoc Bonferroni t tests with results shown if effects were statistically significant.

Treatment	Drug (vs Saline)	Dose	Interaction	Post-Hoc Test
Cocaine versus saline substitution	F1,64 = 22.5; P < 0.001	F4,64 = 18.9; P < 0.001	F4,64 = 19.7; P < 0.001	0.10 mg/kg per inj (t = 5.01, P < 0.001)
				0.32 mg/kg per inj (t = 8.84, P < 0.001)
DTG versus saline substitution	F1,64 = 28.8; P < 0.001	F4,64 = 22.8; P < 0.001	F4,64 = 23.8; P < 0.001	0.32 mg/kg per inj (t = 4.97, P < 0.001)
				1.0 mg/kg per inj (t = 10.1, P < 0.001)
R(+)-SKF 81297 versus saline substitution	F1,20 = 14.4; P = 0.013	F4,20 = 14.1; P < 0.001	F4,20 = 13.2; P < 0.001	1.0 µg/kg per inj (t = 5.40, P < 0.001)
				3.2 µg/kg inj (t = 6.12, P < 0.001)
(±)-SKF 82958 versus saline substitution	F1,20 = 16.3; P = 0.010	F4,20 = 11.5; P < 0.001	F4,20 = 13.1; P < 0.001	1.0 µg/kg per inj (t = 5.29, P < 0.001)
				3.2 µg/kg per inj (t = 6.54, P < 0.001)
R(–)-NPA versus saline substitution	F1,20 = 7.25; P = 0.043	F4,20 = 7.27; P < 0.001	F4,20 = 6.92; P = 0.001	0.32 µg/kg per inj (t = 3.11, P = 0.006)
				1.0 µg/kg per inj (t = 5.02, P < 0.001)
(–)-Quinpirole versus saline substitution	F1,20 = 5.04; P = 0.075	F4,20 = 3.55; P = 0.024	F4,20 = 3.50; P = 0.025	32 µg/kg per inj (t = 4.10, P < 0.001)
Remifentanil versus saline substitution	F1,20 = 7.64; P = 0.040	F4,20 = 6.34; P = 0.002	F4,20 = 6.69; P = 0.001	0.32 µg/kg per inj (t = 3.70, P = 0.002)
				1.0 µg/kg per inj (t = 4.55, P < 0.001)

Inj, injection.