TABLE 1

ED50 values and 95% confidence limits determined before and after Δ9-THC treatment (1 mg/kg per day s.c. for up to 14 days) in monkeys discriminating Δ9-THC

3 Days of Δ9-THC Treatment14 Days of Δ9-THC Treatment
ED50 (95% Confidence Limits)Potency Ratio* (95% Confidence Limits)ED50 (95% Confidence Limits)Potency Ratio* (95% Confidence Limits)
mg/kgmg/kg
Δ9-THC
    Before0.046** (0.021–0.097)0.042 (0.029–0.055)
    1 day after0.13**,# (0.068–0.24)2.8** (1.3–6.4)0.385# (0.293–0.489)9.2 (6.1–13.5)
    7 days after0.042** (0.025–0.077)1.1** (0.5–2.7)
    17 days after0.054 (0.024–0.12)1.6 (0.9–2.7)
CP-55,940
    Before0.005 (0.003–0.007)0.004 (0.003–0.005)
    1 day after0.006 (0.005–0.009)1.4 (0.9–2.1)0.013# (0.01–0.019)3.6 (2.4–5.2)
    9 days after0.006 (0.004–0.008)1.5 (0.9–2.4)
JWH-073
    Before0.048 (0.03–0.067)0.057 (0.049–0.066)
    1 day after0.077 (0.056–0.106)1.6 (1.0–2.4)0.317# (0.126–0.398)5.6 (2.3–8.4)
    9 days after0.08 (0.06–0.11)1.4 (1.0–2.0)
JWH-018
    Before0.024 (0.017–0.034)0.017 (0.016–0.019)
    1 day after0.042 (0.018–0.097)1.8 (0.9–3.5)0.074# (0.047–0.12)4.3 (2.8–6.7)
    9 days after0.014 (0.008–0.24)1.1 (1.0–1.2)

  • ↵* Potency ratios and 95% confidence limits are equal to the ED50 values determined after Δ9-THC treatment divided by the ED50 value determined before daily Δ9-THC treatment.

  • ↵** Data from McMahon (2011).

  • ↵# Significantly different from before.