Suboptimal dietary zinc intake increases aluminum accumulation into the rat brain

The aluminum concentration in the frontal cortex and hippocampus increased when rats were fed semi-synthetic diets containing suboptimal levels of zinc and elevated levels (1000 parts per million, ppm) of aluminum.

Activity of the enzymes dopamine-beta-hydroxylase and phenylethanolamine-N-methyltransferase in discrete brain regions of the copper-zinc deficient rat following aluminum ingestion

We have investigated the possible interactions between the dietary intake of copper, zinc, or aluminum and the activities of the enzymes dopamine-beta-hydroxylase (DBH, EC.1.14.2.1) and phenylethanolamine-N-methyltransferase (PNMT, EC.2.1.1.28) in the male rat brain. Exposure to aluminum was for 120 days at 1000 ppm. The results showed that a diet suboptimal in copper or zinc decreased the activity of both enzymes in the three brain regions studied, including the frontal cortex, hippocampus, and cerebellum. The addition of aluminum to the suboptimal zinc diet restored the activity of both enzymes to within range of control values. The data are discussed with respect to an interaction between zinc and aluminum.

The influence of ingested aluminum upon norepinephrine and dopamine levels in the rat brain

The clinical and neuropathological effects of elevated brain aluminum levels have only recently been described. The clinical symptoms, and localization of aluminum in the brain, suggest an altered catecholamine balance. We report the effects of elevated brain aluminum upon the endogenous steady-state levels of norepinephrine and dopamine in the frontal cortex, hippocampus and cerebellum. The neurotoxic effects of ingested aluminum are shown to be dependent upon the dietary intake of copper, zinc, iron, and magnesium. Norepinephrine levels in the cortex and cerebellum decreased in rats fed a low copper diet with aluminum added (0.1%, w/w). Suboptimal iron levels decreased norepinephrine in the cerebellum. The presence of aluminum in diets low in copper or zinc decreased dopamine levels in the cortex. The data are interpreted with respect to the clinical symptomatologies seen in demented, chronic renal dialysis patients with depressed serum copper and zinc levels.