TABLE 1.

Effects of extended history of drug self-administration on the induction of reinforcing effects of the σ₁R agonist, PRE-084

Training Drug	Cumulative Intake of the Training Drug	Maximal Response Rate Maintained by PRE-084	Maximal Response Rate Maintained by the Training Drug
	mg/kg	responses/sec at mg/kg per injection
d-Methamphetamine	64.7 ± 6.75	0.184 ± 0.056 at 0.32	0.086 ± 0.015 at 0.10
	163 ± 21.3	0.388 ± 0.177 at 0.32	0.068 ± 0.011 at 0.10
	243 ± 34.0	0.339 ± 0.145 at 0.32	0.068 ± 0.011 at 0.10
Heroin	3.73 ± 0.292	0.021 ± 0.004 at 1.0	0.064 ± 0.012 at 0.01
	23.7 ± 3.45	0.018 ± 0.004 at 3.2	0.070 ± 0.012 at 0.01
Ketamine	367 ± 30.7	0.028 ± 0.007 at 0.32	0.376 ± 0.100 at 0.32
	1630 ± 141	0.023 ± 0.004 at 0.32	0.427 ± 0.120 at 0.32