Aluminum toxicity and behavior in the weanling Long-Evans rat

Muricidal behavior, weight, open-field activity, passive-avoidance learning, and learning of an eight-arm radial maze were assessed in Long-Evans hooded rats subjected as weanlings to 60 days of oral administration of aluminum hydroxide gel (Group AA) or tap water (Group NA). Measurement of brain aluminum content indicated that the groups did not differ significantly in neural incorporation of aluminum, although the median amount of aluminum in each brain area examined was higher for Group AA than for Group NA. Although the highest brain concentrations of aluminum were found in the hippocampus, there was no evidence for cognitive impairment in the present study. Aluminum-exposed rats weighed less than nonexposed animals at all weight periods, probably reflecting their initially decreased fluid intake. There was slight evidence for activity changes as a function of brain aluminum content. Age of the animals appears to be an important consideration in the study of aluminum toxicity in rats, with young animals less affected than older animals.