TABLE 1

Effective doses, their 95% confidence limits, and relative potencies with which cannabinoid CB₁ receptor agonists, cannabinoid CB₁ receptor antagonists, and dopaminergic and opioid drugs decreased schedule-controlled behavior in squirrel monkeys before and during repeated exposure to the cannabinoid CB₁ receptor agonist AM411 (1.0 mg/kg per day)

Italicized data represent significant difference in relative potency values between prechronic versus chronic effects of drugs.

Drug		Prechronic Doses	Prechronic ED₅₀ (95% CL)	Chronic Doses	Chronic ED₅₀ (95% CL)	Relative Potency: Prechronic versus Chronic (95% CL)
		mg/kg	mg/kg	mg/kg	mg/kg
CB₁ agonists	AM411	0.01–1.0	0.26 (0.08–5.24)	0.32–100	ND	ND
	AM4054	0.003–0.1	0.02 (0.01–0.07)	0.1–3.2	0.95 (0.32–11.29)	0.02 (0.01–0.04)
	WIN55,212.2	0.032–1.0	0.26 (0.10–1.20)	3.2–32	23.05 (11.81–24.38)	0.01 (0.003–0.028)
	Δ⁹-THC	0.1–3.2	0.74 (0.33–2.11)	3.2–100	57.27 (22.73–1479.82)	0.02 (0.006–0.065)
	Methanandamide	1–10	NS	10–320	ND	ND
CB₁ antagonists	SR141716A	3.2–18	14.27 (10.85–22.01)	0.01–0.32	0.13 (0.04–1273.51)	221 (83.1−715)
CB₁ antagonists	AM4113	1.0–10	5.97 (2.98–53.22)	0.032–1.0	0.25 (0.08–1.72)	31.54 (12.17–102.35)
Indirect DA agonist	Methamphetamine	0.032–0.32	0.20 (0.09–4.80)	0.1–3.2	0.96 (0.44–3.57)	0.26 (0.09–0.90)
DA D₁ agonist	SKF82958	0.032–1.0	0.18 (0.09–0.37)	0.032–1.0	0.11 (0.06–0.17)	1.58 (0.83–3.19)
DA D₁ antagonist	SCH23390	0.01–0.032	ND	0.01–0.1	ND	ND
DA D₂ agonist	R-(−)-NPA	0.003–0.01	0.006 (0.004–0.01)^{^a}	0.003–0.1	0.05 (0.03–0.15)	0.18 (0.05–0.49)
DA D₂ antagonist	Haloperidol	0.003–0.1	0.04 (0.02–0.07)	0.003–0.32	0.03 (0.02–0.06)	1.19 (0.61–2.49)
Opioid agonist	Morphine	0.32–3.2	1.39 (0.75–3.37)	0.32–10	2.99 (1.36–11.56)	0.52 (0.23–1.12)
Opioid antagonist	Naltrexone	1.0–10	ND	1.0–10	ND	ND

95% CL, 95% confidence limits; DA, dopamine; ND, not determined; NS, nonsignificant regression.
↵^a Significant deviation from linearity.