Features of memory on novel situation and avoidance response: evidence from comparisons between open-field behavior and step-through task.
AIM
To study the features of memory on novel situation and avoidance response in mice.


METHODS
Open-field activity and step-through latency were used to determine the memory of mice on a new environment and avoidance, respectively.


RESULTS
The open-field memory was only observed 24 and 48 h after acquisition session. The avoidance memory still existed 72 and 96 h after training session. On d 1 mice were allowed to remain on open-field and step-through for 0.5, 1, 3, and 5 min. On d 2 the retention latencies in 0.5- and 1-min groups were shorter than those in 3- and 5-min groups, while the recall activities in open-field were indifferent between these groups. Scopolamine (1 mg.kg-1) and caffeine (200 mg.kg-1) injected ip 15 min before the first session inhibited the avoidance response and the adaptation to open-field environment in mice. Chlorpromazine, promethazine, picrotoxin and pentobarbital impaired the avoidance memory, but not impaired the open-field memory.


CONCLUSION
These results supported the hypothesis that the adaptation of mice on open-field was a short or medium term memory.