Nicotine and caffeine: Disruption of the long-term store of memory and proactive facilitation of learning in mice.

The effects of nicotine and caffeine on the long-term store of memory in mice were determined for a wide range of dosages. Male F mice (C57BL/6J×DBA/ 2J) were given two trials in an appetitive maze 24 h apart. Twenty-four hours after the second trial each animal was given the first of five daily injections of one of the dosages being tested. Beginning 48 h after the last injection, animals received one trial per day until a learning criterion was reached. Both nicotine and caffeine produced a dose-dependent disruption of performance in the trials following the injection series. In contrast, nicotine produced facilitation of performance in animals given a series of injections in the absence of previous training, and caffeine produced a strong trend in this direction. It was concluded that these drugs produced disruption of the long-term store of memory for the initial training and proactive facilitation of maze learning. The existence of separate and opposing effects of these drugs on different aspects of learning and memory was discussed. [ABSTRACT FROM AUTHOR]