Fig 2.

(EXP-2): Average (± S.E.M.) effects of i.p. administered 3 mg/kg Δ⁹-THC alone (1^st and last bar) and in combination with 1 mg/kg rimonabant on the rate of responding in rats (n = 8) maintained on a FR-10 schedule of food reinforcement. Y-axis: response rate where 1 represents unity (dashed line), i.e., rate being equal to the base-line rate observed in each individual animal during preceding non-drug sessions. X-axis, time elapsed since injection (Δ⁹-THC was always administered 20 min before session onset) and dose in mg/kg (Δ⁹-THC, 3 mg/kg; rimonabant, 1 mg/kg). Data points are based on one observation for 7 to 8 individual animals. Functional in vivo half-life and the ±95% confidence limits (±95% C.L.) estimated by non-linear regression (Prism, v. 5). +) signifies that the response rate observed at 20 min post administration (Δ⁹-THC plus rimonabant) is significantly higher than the response rates observed with 3 mg/kg Δ⁹-THC alone (together with vehicle) as well as the response rate observed 8 h after rimonabant plus Δ⁹-THC administration; *) signifies that the response rate observed at 60 min post administration (Δ⁹-THC plus rimonabant) is significantly higher than the response rates observed with 3 mg/kg Δ⁹-THC alone (Holm-Sidak all pair-wise multiple comparison procedure).