Fig. 4.

Generalization test results (top) and corresponding response rate data (bottom) for AM1346 (n=8–11), Δ⁹-THC (n=7–10), and mAEA [R-(+)-methanandamide; n=8], as well as for D-amphetamine (D-Amph., n=10) and morphine (Morph., n=10) in AM1346- (5.6 mg/kg) versus vehicle-trained rats; sessions began 20 min after i.p. administration. The generalization results represent the mean (±SEM) percentage of lever presses on the drug (5.6 mg/kg AM1346) appropriate lever out of the total number of lever presses emitted during a test session (Y axis); doses examined in milligram per kilogram (X axis). Rate refers to the mean (±SEM) number of lever presses per second emitted during a test session (Y axis); doses in milligram per kilogram (X axis). Dotted lines represent the ±95% confidence limits of vehicle control response rate determined from the initial six reinforcement cycles of the vehicle training sessions preceding these tests; symbols outside the confidence limits are considered significantly different from control. Data points are based on one observation for each rat and were obtained on separate test days. Numbers within brackets indicate the number of rats responding (i.e., obtaining at least one reinforcement) out of the total number used for the test; note that (4/10) refers to Δ⁹-THC (rather than AM1346). Data are based on test sessions of a maximum of six reinforcers or 20 min, whichever occurred first. V Vehicle