Prevention of memory loss for a brightness change in adult and middle-aged rats by postacquisition treatment with glucose.

Following 2 h of unrestricted access to a black and a white arm of a Y maze, 8-month-old "adult" and 21-month-old "middle-aged" rats were injected intraperitoneally with 0 (vehicle), 50 or 100 mg/kg D-glucose. Twenty-four hours later they were allowed free access to two black arms. When treated with vehicle, there was no evidence of any memory for change as determined by first and total entries of, and time spent in the changed arm. However, the adult "younger" rats showed significant awareness of the changed arm following treatment with the higher dose of glucose. It was concluded that, for adult rats only, treatment with glucose prevented forgetting of their pretreatment experience with the maze arms thereby enabling detection and choice of the changed alternative. It was also suggested that the experimental procedure might have potential as a measure of memory, in particular, one not dependent on deprivation and reinforcement, in the absence of current effects of glucose or other enhancing agents.