Phencyclidine-like discriminative stimulus properties of the stereoisomers of dioxadrol.

Rats (N=6) were trained to discriminate 3.0 mg/kg i.p. phencyclidine (PCP) from saline in a 2-lever fixed-ratio 32 operant discrimination procedure for food presentation. Generalization tests were conducted with other doses of PCP as well as with various doses of the stereoisomers of dioxadrol. Dose-dependent PCP-like discriminative stimulus effects were obtained with dexoxadrol but not with levoxadrol, however overall rates of responding were decreased to a comparable extent by 30 mg/kg of both compounds. PCP was 3.6 times more potent than dexoxadrol in producing stimulus control of responding. These data provide some evidence for stereoselectivity of action for dioxadrol, however nonPCP-like effects of levoxadrol are present at doses only 3 times greater than those doses of dexoxadrol that result in PCP-lever responding. Therefore, absolute stereospecificity beyond 3-fold cannot be demonstrated by these data.