Pre-exposure to related substances induced place preference and self-administration of the NMDA receptor antagonist-benzodiazepine combination, zoletil.

Previously, we have reported that the N-methyl-D-aspartate (NMDA) receptor antagonist-benzodiazepine veterinary anesthetic combination, zoletil, produced reward and reinforcement, but only in rats repeatedly pretreated with the drug and not in drug-naïve rats. Therefore, we hypothesized that previous drug exposure plays an important role in the abuse of zoletil. In the present study, we examined whether pre-exposure to related substances, NMDA receptor antagonists (tiletamine, ketamine), and benzodiazepines (zolazepam, diazepam) predisposes animals to abuse zoletil.