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Effects of Taurine and Mitochondrial Metabolic Inhibitors on ATP‐Dependent Ca 2+ Uptake in Synaptosomal and Mitochondrial Subcellular Fractions of Rat Retina
Author(s) -
Lombardini John B.
Publication year - 1988
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1988.tb04856.x
Subject(s) - taurine , oligomycin , mitochondrion , biochemistry , ruthenium red , chemistry , biology , enzyme , calcium , atpase , amino acid , organic chemistry
ATP‐dependent Ca 2+ uptake was investigated at low Ca 2+ concentrations (10 μ M ) in rat retinal synaptosomal and mitochondrial preparations obtained by differential centrifugation on Ficoll gradients. Ca 2+ uptake in the synaptosomal and mitochondrial subcellular preparations was stimulated by ATP and additionally stimulated by ATP plus taurine. The ATP‐dependent and taurine‐stimulated ATP‐dependent Ca 2+ uptakes were inhibited by mitochondrial metabolic inhibitors (atractyloside, oligomycin, and ruthenium red). These metabolic inhibitors had a greater effect on the ATP‐dependent and taurine‐stimulated ATP‐dependent Ca 2+ uptake activities in the mitochondrial preparation than in the synaptosomal preparation. ATP‐dependent Ca 2+ uptake in a synaptosomal subfraction obtained by osmotic shock was only partially inhibited by atractyloside. ATP‐dependent Ca 2+ uptake in the synaptosomal subfraction was also stimulated by taurine but to a lesser extent than in either the synaptosomal or mitochondrial preparation. These studies suggest that mitochondria are primarily responsible for taurine‐stimulated ATP‐dependent Ca 2+ uptake in synaptosomal preparations.