TABLE 1

Discriminative stimulus effects of saline and test drugs administered alone

Drug	E_max (% DAR)		ED₅₀ (mg/kg)		Slope
Drug	Mean	(S.E.M.)	Mean	(95% CI)	Mean	(S.E.M.)
Cocaine^{^a}	100	(0.0)	4.9	(4.2–5.9)	1.7	(0.08)
Saline	1.8	(1.5)^*	n.a.	n.a.	n.a.	n.a.
Caffeine^{^a}	77.5	(6.3)^*	14.4	(9.5–21.9)	1.2	(0.12)
MDPV	98.3	(1.1)	0.39	(0.25–0.58)	2.1	(0.33)
Methamphetamine	99.8	(0.2)	0.37	(0.34–0.41)	2.3	(0.32)
Midazolam	7.6	(5.0)^*	n.a.	n.a.	n.a.	n.a.

n.a., not applicable.
↵^a E_max, ED₅₀, and slope parameters were derived from two sets of dose-response curves determined in triplicate (i.e., six dose-response curves).
↵* Significant difference from cocaine as determined by one-way analysis of variance with repeated measures and post-hoc Dunnett’s test for multiple comparisons.