Differential aversive stimulus properties of beta-phenylethylamine and of d-amphetamine.

In a conditioned taste-aversion experiment with male Wistar rats (two-bottle test, single pairing), the effects of beta-phenylethylamine (PEA 12.5, 25.0, 50.0, 100.0 mg/kg IP) and of d-amphetamine (2.5 mg/kg IP) were compared with the effect of the saline vehicle. The amphetamine-treated group exhibited a marked aversion to saccharin on each of four retention trials. A decrease in saccharin intake after PEA was limited to the highest dose group (100 mg/kg) and the first retention trial for that group. Doses of up to 50 mg/kg of PEA were also ineffective with a single-bottle conditioned taste-aversion procedure involving multiple conditioning trials, although doses of 25 and 50 mg/kg of PEA induced marked changes in spontaneous motor activity. These data demonstrate that behaviourally active doses of PEA are ineffective in inducing a conditioned taste aversion to saccharin. This result extends previous reports that structurally similar compounds may have different potencies in this paradigm. It is proposed that further studies of structure-activity relationships may help to reveal the features of drug action that are necessary for the induction of a conditioned taste aversion.