Cross-generalization between an ethologically [correction of ecologically] relevant stimulus and a pentylenetetrazole-discriminative cue.

Twelve male Sprague-Dawley rats were trained in a two-choice pentylenetetrazole vs. saline drug discrimination (DD) task under an FR10 schedule of food reinforcement. Two-minute reinforced test sessions with the two training stimuli engendered exclusive injection-appropriate responding. Rats were injected with saline and then exposed for 20 min to the presence of a domestic cat pretreated with catnip. Immediately following the predator exposure, rats were tested for stimulus generalization in the DD task. The predator/prey interaction engendered 92% PTZ-appropriate responding. These data suggest that the interoceptive state associated with species-specific defense reactions in rats is similar to the cues produced by a pharmacological agent within a behavioral assay which has been suggested as an animal model of human anxiety.