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Neurotransmitter Metabolism in Rat Brain Synaptosomes: Effect of Anoxia and pH
Author(s) -
Pastuszko Anna,
Wilson David F.,
Erecińska Maria
Publication year - 1982
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.1471-4159.1982.tb06647.x
Subject(s) - neurotransmitter , veratridine , dopamine , synaptosome , serotonin , medicine , endocrinology , biology , metabolism , catecholamine , chemistry , biochemistry , sodium , central nervous system , receptor , organic chemistry , sodium channel
Synaptosomes isolated from the rat cerebral cortex by means of a discontinuous Ficoll gradient carry out net, sodium‐dependent, veratridine‐sensitive accumulation of γ‐aminobutyric acid (GABA), serotonin, norepinephrine, and dopamine. The intrasynaptosomal contents of the four neurotransmitters are: 30.4 nmol/mg protein, 17.4 pmol/mg protein, 13.5 pmol/mg protein, and 21.2 pmol/mg protein, respectively. Anaerobic preincubation of synaptosomes causes an irreversible decrease in the rates of neurotransmitter accumulation but does not affect the rates of their release. The inhibitory effect of anaerobiosis is enhanced by increased concentration of [H + ] (decreased pH) in the medium. The most sensitive is the uptake of dopamine, the least that of serotonin. The rates of neurotransmitter efflux are unaffected by anaerobiosis. Synaptosomes leak catecholamines, GABA, and serotonin into the medium when subjected to anaerobiosis, and reintroduction of oxygen is accompanied by a rapid reaccumulation of all four neurotransmitters. It is concluded that: (1) Responses of synaptosomes to anaerobiosis are remarkably similar to the behavior of intact brain in hypoxia and ischemia. (2) Neurotransmitter uptake systems are more sensitive to short periods of anaerobiosis than are either the energy metabolism or ion transport. (3) Some neurotransmitter uptake systems are more easily damaged by anaerobiosis than others.