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High‐Affinity Uptake of [ 3 H]Norepinephrine by Primary Astrocyte Cultures and Its Inhibition by Tricyclic Antidepressants
Author(s) -
Kimelberg Harold K.,
Pelton E. Williams
Publication year - 1983
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.1471-4159.1983.tb13565.x
Subject(s) - desipramine , tricyclic , norepinephrine , astrocyte , kinetics , chemistry , synaptosome , non competitive inhibition , pharmacology , biophysics , medicine , endocrinology , biology , biochemistry , membrane , stereochemistry , dopamine , enzyme , central nervous system , hippocampus , antidepressant , physics , quantum mechanics
Primary astrocyte cultures from neonatal rat brains show uptake of [ 3 H]norepinephrine ([ 3 H]NE). This uptake has a high‐affinity component with an apparent K m of approximately 3 × 10 −7 M . At 10 −7 M [ 3 H]NE both the initial rate of uptake and steady‐state content of [ 3 H]NE is inhibited by up to 95% by omission of external Na + . The Na + ‐dependent component of this uptake is totally inhibited by the tricyclic antidepressants desipramine (DMI) and amitryptyline with IC 50 values of 2 × 10 −9 and 4 × 10 −8 M , respectively. Inhibition of [ 3 H]NE uptake by DMI shows competitive kinetics. These characteristics are essentially identical to those found for high‐affinity uptake of NE in total membrane or synaptosome fractions from rodent brains and suggests that such uptake in neural tissue is not exclusively neuronal.