Chronic, oral aluminum administration to rats: cognition and cholinergic parameters

Administration of aluminum sulfate in the drinking water of male Sprague-Dawley rats for thirty days resulted in an impairment of both consolidation and extinction of a passive avoidance task. No impairment of performance was observed on an active avoidance task, radial arm maze or open field activity measure. Biochemical analysis indicated a slight (less than 10%) but significant increase in hippocampal muscarinic receptor number after aluminum treatment as determined by tritiated quinuclidinyl benzilate (3H-QNB) binding. No changes were found in choline acetyltransferase (ChAT) activity, phosphoinositide hydrolysis, 3H-QNB binding in the cortex or tritiated pirenzepine (3H-PZ) binding in the hippocampus or cortex. These results indicate that cholinergic degeneration was not the cause of the observed cognitive impairments.