Combined effect of metals on biogenic amines and their distribution in the brain of mice.

The toxic effects of manganese in combination with iron or copper on the brain tissue of mice were investigated. The combined administration of manganese and iron decreased the accumulation of manganese in the brain compared to manganese treatment alone. This indicated that excess iron may influence the absorption of manganese. Combined exposure to manganese and copper resulted in marked accumulation of copper in the brain. This is of great concern, since excess copper in brain produces incoordination in body movements. Thus, the combined exposure of these two metals, even in permissible limits, may produce serious brain dysfunctions. The combined administration of manganese with iron or copper has also significantly altered the levels of brain tryptophan and 5-hydroxytryptamine.