Residual effects of prolonged cannabis treatment on shuttle-box avoidance in the rat.

Chronic oral administration of cannabis extract to rats was examined for its residual effects on shuttle-box avoidance learning. In experiment 1 avoidance learning was assessed in rats that had been tested previously on other behavioral tests. Chronic treatment (3 months) facilitated the learning of shuttle-box avoidance in cannabis-treated animals relative to vehicle controls. In experiment 2 very similar results were obtained in naive rats. These and other residual effects of chronic cannabis treatment are similar to the effects of hippocampal lesions.