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STIMULATED INCORPORATION OF AMINO ACIDS INTO PROTEINS OF SYNAPTOSOMAL FRACTIONS INDUCED BY DEPOLARIZING TREATMENTS
Author(s) -
Wedege E.,
Luqmani Y.,
Bradford H. F.
Publication year - 1977
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.1471-4159.1977.tb10702.x
Subject(s) - cycloheximide , synaptosome , amino acid , tetrodotoxin , chemistry , depolarization , protein biosynthesis , biochemistry , biophysics , membrane , biology
— Rat cortical synaptosome preparations incorporated l ‐amino acids into protein at a linear rate over 30–60 min. Synaptosomes showed large increases in incorporation after treatment with electrical pulses, veratrine or K + . This was inhibited (controls, 73%; electrically stimulated 58%) by cycloheximide and by chloramphenicol (28 and 44% respectively). Omission of Ca 2+ from the medium had no effect, but the absence of Na + greatly diminished the stimulus‐induced increase in incorporation due to pulses. Electrical pulses, veratrine and K + (in order of effectiveness), all showed their greatest proportional effects on amino acid incorporation into the Triton‐X‐100 insoluble portions of the synaptosomal membrane: the ‘junctional complex’, soluble in SDS, and the residue. Tetrodotoxin (1 μ m ), although ineffective when potassium was the stimulus, prevented or reduced the respiratory response, K + loss and differential amino acid release, as well as the amino acid incorporation into protein observed with pulses and veratrine. C‐6 glioma cells showed no stimulus‐dependent increase in incorporation. Preliminary data, of gel electrophoretic analysis, on the proteins labelled under our conditions is presented.