[Training and extinction of passive avoidance in mice lacking monoamine oxidase A]

The passive avoidance learning and memory trace retention in mice lacking monoamine oxidase A (MAO A) and control C3H strain were analyzed. It is shown that mice of both strains were well the passive avoidance learners. A delay of the memory trace extinction was found in lacking MAO A mice as compared with control C3H strain. Mice with a genetic MAO A knockout showed decreased amounts of transitions, rearings, looking to a dark compartment and appearing from it. These findings seem to reflect more expressed fear reaction to a dangerous compartment and increased anxiety promoting longer retention of memory trace on a high level of retrieval.