Palacios Javier, Sepúlveda M Rosario, Lee Anthony G, Mata Ana M
Departamento de Bioquímica y Biología Molecular y Genética, Facultad de Ciencias, Universidad de Extremadura, 06071 Badajoz, Spain.
Biochemistry. 2004 Mar 2;43(8):2353-8. doi: 10.1021/bi0359473.
Thioridazine inhibits the activity of the synaptic plasma membrane Ca(2+)-ATPase from pig brain and slightly decreases the rate of Ca(2+) accumulation by synaptic plasma membrane vesicles in the absence of phosphate. However, in the presence of phosphate, thioridazine increases the rate of Ca(2+) accumulation into synaptic plasma membrane vesicles. Phosphate anions diffuse through the membrane and form calcium phosphate crystals, reducing the free Ca(2+) concentration inside the vesicles and the rate of Ca(2+) leak. The higher levels of Ca(2+) accumulation obtained in the presence of thioridazine could be explained by a reduction of the rate of slippage on the plasma membrane ATPase.
