Rivastigmine reverses aluminum-induced behavioral changes in rats.

Aluminum, a known neurotoxin, has long been implicated in the pathogenesis of Alzheimer's disease. Its exposure is associated with impairment in the cholinergic system in the brain. In this study we investigated the behavioral effects of aluminum in rats and the possible effect of rivastigmine, a cholinesterase inhibitor, on the aluminum-induced behavioral changes. Rats were exposed to aluminum chloride (100 mg/kg/day i.p.) for 60 days before the start of behavioral tests. Rivastigmine was given in doses of 0.5, 1, 1.5 and 2.5 mg/kg i.p. 60 min before the behavioral tests. Five tests were investigated; open field test, Morris water maze, radial arm maze, passive avoidance test and rota-rod test. Results showed that aluminum exposure was associated with significant reductions in spontaneous locomotor and exploratory activities in open field test and significant impairments in learning and memory in Morris water maze, radial arm maze and passive avoidance tests. The behavioral impairments caused by aluminum were significantly improved by rivastigmine. Neither aluminum alone nor co-treatment with rivastigmine caused any significant alteration of the animals' performance in rota-rod test. The improvements in activity, learning and memory caused by rivastigmine were found to be dose-dependent, and the maximal improvement was encountered with its large dose (2.5 mg/kg). From these results we can conclude that rivastigmine can reverse behavioral deficits caused by aluminum intoxication.