Models & Assays

All drugs of abuse, as well as certain non-abused drug classes, will produce an internal state that the rat can be trained to discriminate from a neutral stimulus such as saline injection. Drug discrimination procedures typically rely on a two-lever operant procedure. NCE’s may be tested for (a) their ability to either substitute (generalise) to a known drug cue (i.e suggestive of a similar interoceptive state) or (b) their ability to antagonise a known drug cue (i.e suggestive of an ability to block the interoceptive state of a known drug). Alternatively rats may be trained with an NCE to see if it can support a discrimination opening up opportunities to identify which known drugs may generalise. Transpharmation has experience in each of these areas.

Separate groups of rats were trained to discriminate either nicotine (0.3 mg/kg) from saline (Nicotine), or Diazepam (2 mg/kg) from saline (DZP). As expected Nicotine trained rats showed a dose related generalisation to the nicotine lever, and DZP trained rats showed a dose related generalisation to the diazepam lever. However diazepam administered to Nicotine group, and nicotine administered to DZP group produced only at best a very weak (~25%) generalisation, thus showing the specificity of each cue type.