ON THE MECHANISM OF OUABAIN INHIBITION OF SYNAPTOSOME PROTEIN SYNTHESIS |
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| Authors: | M Anthony Verity W Jann Brown Marshall K Cheung |
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| Institution: | Department of Pathology (Neuropathology), Brain Research Institute and Mental Retardation Center, University of California Center for the Health Sciences, Los Angeles, CA 90024, U.S.A. |
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| Abstract: | Abstract— Ouabain (200μ m ) inhibited incorporation of radiolabelled leucine or glycine into the protein of neonatal synaptosome fractions but had minimal effect on preparations from adult rats. Leucine uptake into synaptosomes was rapid but not influenced by 200μ m -ouabain in contrast to ouabain inhibition of 14C]glycine and 14C]γ-aminobutyric acid uptake. Ouabain blocked the Na+ -dependent (stimulated) component of synaptosome fraction protein synthesis in the presence of 25m m -K+. Ouabain inhibition was not alleviated by addition of ADP or ATP. 100μ m -atractylate failed to influence 3H]leucine uptake or incorporation. Synergistic inhibition by ouabain was observed with the cycloheximide-sensitive component of protein synthesis and the chloramphenicol sensitive phase. Increasing the medium Ca2+ concentration stimulated protein synthesis and this stimulated component was inhibited by ouabain. Ouabain inhibition was associated with decreasing intraterminal K+ concentration and K]i was linearly related to the protein synthesis rate in control and ouabain treated preparations. |
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