ATP IN CELLULAR CALCIUM-OVERLOAD BY TRIVALENT METAL-IONS

Extracellular Ca2+-influx induced by trivalent metal ions (Fe3+, Al3+, Cr3+, In3+, Ga3+, and La3+) in Ehrlich carcinoma cells is enhanced by ATP. This action seems to be related to the high coordination capacit y of the ATP ligand that inhibits the polymerization of the solvated c ations taking place at physiological pH, and consequently permits thei r biological activity. A general relationship between induced lipid pe roxidation and increased calcium uptake was not found. These results e mphasize the Am role in the toxicity of trivalent metals, and its poss ible involvement, via cellular calcium overload, in a neurodegenerativ e process, such as Alzheimer's and Parkinson's diseases, in whose etio logy the implication of aluminum and iron has been suggested.