High-affinity uptake of [3H]norepinephrine by primary astrocyte cultures and its inhibition by tricyclic antidepressants.
Primary astrocyte cultures from neonatal rat brains show uptake of [3H]norepinephrine ([3H]NE). This uptake has a high-affinity component with an apparent Km of approximately 3 X 10(-7) M. At 10(-7) M [3H]NE both the initial rate of uptake and steady-state content of [3H]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 IC50 values of 2 X 10(-9) and 4 X 10(-8) M, respectively. Inhibition of [3H]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.
D000639:Amitriptyline / Q000494:pharmacology*; D000818:Animals; D000831:Animals, Newborn; D001253:Astrocytes / Q000187:drug effects / Q000378:metabolism*; D001692:Biological Transport / Q000187:drug effects; D002478:Cells, Cultured; D003891:Desipramine / Q000494:pharmacology*; D004298:Dopamine / Q000494:pharmacology; D007700:Kinetics; D009638:Norepinephrine / Q000378:metabolism*; D051381:Rats
D000639:Amitriptyline; D003891:Desipramine; D004298:Dopamine; D009638:Norepinephrine