EFFECT OF MESCALINE AND LYSERGIC ACID DIETHYLAMIDE ON FLICKER DISCRIMINATION IN THE RAT

¹ Department of Pharmacology, School of Medicine, State University of New York at Buffalo, Buffalo, New York

Rats were trained on a multiple schedule of positive reinforcement. A stationary light source flickering at 100 cps provided the discriminative stimulus (S^d). In the presence of S^d, reinforcement was contingent upon a fixed ratio 10 schedule. The same light source flickering at either 20 or 30 cps constituted the S period. Mescaline, at doses of 40 and 60 µmole/kg, produced a significant decrease in discriminative ability, whereas lysergic acid diethylamide (0.2, 0.3 and 0.4 µmole/kg) caused a significant increase. A dose of mescaline (20 µmol/kg) which by itself had no significant effect on discrimination, significantly reduced the increase caused by lysergic acid diethylamide. Likewise, a subeffective dose of lysergic acid diethylamide (0.1 µmol/kg) significantly antagonized the depression of discriminative ability caused by mescaline. These results indicate that flicker discrimination provides a sensitive measure of drug action in the rat. The pharmacologic data suggest that lysergic acid diethylamide and mescaline are mutually antagonistic in this system.