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Published on: May 19, 2017
Ca2+ transport by the synaptosomal plasma membrane Ca2+-ATPase and the effect of thioridazine
Javier Palacios1, M Rosario Sepúlveda, Anthony G Lee
1Departamento de Bioquímica y Biología Molecular y Genética, Facultad de Ciencias, Universidad de Extremadura, 06071 Badajoz, Spain.
Abstract:
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.
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