THE EFFECTS OF ANXIOLYTICS AND ANXIOGENICS ON EVALUATION OF LEARNING AND MEMORY IN AN ELEVATED PLUS-MAZE TEST IN MICE

We examined the effects of anxiolytics and anxiogenics on evaluation o f learning and memory in rite elevated plus-maze test in mice. Transfe r latency (TL), the rime mice took to move from the open arm to the en closed arm, was used as an index of learning and memory. The TL on day 2 was shorter than that on day 1 with the maze at a height of 40 cm, and was nor affected by anxiolytics and anxiogenics such as 8-OH-DPAT (0.4 mg/kg), picrotoxin (2 mg/kg), and FG-7142 (20 mg/kg), but was aff ected by diazepam (8 mg/kg). On the other hand, the TL on day 2 was pr olonged by changing the experimental room between day I and day 2. TL on day 2 was prolonged by treatment with scopolamine before the trial on day 1 compared with vehicle-treated groups. This scopolamine-induce d prolongation of TL was reversed by pretreatment with physostigmine a nd piracetam. The TL on day 2 was also prolonged by treatment with cyc loheximide or normobaric hypoxia initiated immediately after the trial on day 1. The cycloheximide- and hypoxia-induced prolongation of TL w ere reversed by pretreatment with piracetam. These results indicate th at disruption of learning and memory and its amelioration, induced by the treatments described above, can be detected using the plus-maze te st, suggesting that rite elevated plus-maze test could be used for eva luation of learning and memory without influence of anxiolytics and an xiogenics.