Glucose minimally attenuates scopolamine-but not morphine-induced deficits on a water maze alternation task.

In a previous study, daily injections of glucose, 100 and 250 mg/kg i.p., in Sprague-Dawley rats failed to either facilitate acquisition or to ameliorate scopolamine- or morphine-induced deficits on a water maze alternation task (Means, et al., 1996). The present study demonstrates that daily injections of 1 g/kg minimally ameliorates a scopolamine-induced deficit on the water maze alternation task in Sprague-Dawley rats. However, daily glucose injections of 1, 2 and 4 g/kg failed to improve performance during acquisition or to diminish morphine-induced deficits on the task. The failure of daily administration of glucose to facilitate acquisition or reverse morphine-induced deficits was not due to the daily injection procedure nor to stress elevated glucose levels resulting from exposure to the task. It is suggested that the effects of glucose on memory are task dependent, with facilitation being more easily demonstrated on tasks for which animals have an innate bias to perform the correct response or the ability to acquire in very few trials.