Premium
IN VITRO Ca 2+ DEPENDENT PROTEOLYSIS IN BRAIN TISSUES: A POSSIBLE SOURCE OF ERROR IN TRANSMITTER METABOLISM STUDIES
Author(s) -
Hamon M.,
Bourgoin S.,
Hery F.,
Glowinski J.
Publication year - 1974
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.1471-4159.1974.tb04412.x
Subject(s) - tyrosine , tryptophan , metabolism , proteolysis , in vitro , chemistry , methionine , amino acid , serotonin , biochemistry , phenylalanine , hippocampal formation , medicine , endocrinology , biology , enzyme , receptor
—The effects of Ca 2+ ions on the metabolism of [ 3 H]serotonin and [ 3 H]‐labelled catecholamines have been examined in hippocampal slices or synaptosomes. The formation of [ 3 H]‐5 hydroxyindoles ([ 3 H]serotonin + [ 3 H]‐5 hydroxyindoleacetic acid) from [ 3 H]tryptophan and that of [ 3 H]‐labelled catecholamines from [ 3 H]tyrosine were increased when Ca 2+ was omitted from the incubating medium. However, the total synthesis of 5‐HT from tryptophan and that of catecholamines from tyrosine did not seem to be significantly changed. Altered formation of tritiated amines were due to changes in the specific activities of respective precursor amino acids. This reflected altered sizes of the free amino acid pools caused by Ca 2+ ‐dependent in vitro proteolysis. This must be taken into consideration when studying in vitro Ca 2+ dependency of neutrotransmitter metabolism.