Comparison of the discriminative stimulus properties of Δ9-THC and psilocybin in rats

Male albino rats learned to press either a left or right lever depending on which drug they had received 30 minutes earlier. One group discriminated between 1.9 mg/kg of delta9-THC and a vehicle control; another group discriminated between 1.0 mg/kg of delta9-THC and 1.0 mg/kg of psilocybin. The results confirmed that delta9-THC can serve as a discriminative stimulus controlling behavior. Because rats reliably chose different levers after delta9-THC versus psilocybin, the two drugs likely produce distinct internal states in rats.

Study at a glance

Abstract

Male albino rats were trained to respond differentially on the left or right lever in a 2-lever chamber on the basis of which drug had been given intra-peritoneally (IP) 30 min before experimentation. In 1 group 1.9 mg/kg of delta9-THC and control injections (vehicle) served as the discriminative stimuli associated with each lever and in another group the drug stimuli were 1.0 mg/kg of delta9-THC and 1.0 mg/kg of psilocybin. The results confirmed those of other experiments using different procedures; that delta9-THC can acquire discriminative control over responding. The fact that delta9-THC and psilocybin were also found to differentially control lever choice demonstrates that these 2 drugs probably produce discriminably different states in rats.