Background:

Atomoxetine HCl is a selective norepinephrine transporter inhibitor (Ki= 5 nM)

Norepinephrine transporter is a multi-pass membrane protein that is essential for norepinephrine reuptake into presynaptic nerve terminals and regulates norepinephrine homeostasis.

Atomoxetine blocked coupling of radioligands to clonal cell lines that transfected with human norepinephrine transporter, serotonin and dopamine transporters with Ki= 5, 77 and 1451 nM respectively. [1]

In microdialysis studies in rat, atomoxetine increases extracellular levels of norepinephrine transporter in prefrontal cortex 3-fold without altering 5-HTEX levels. Atomoxetine also increases DAEX concentrations in PFC 3-fold without altering DAEX in striatum or nucleus accumbens. Comparing with methylphenidate, atomoxetine do not increase DA in striatum or nucleus accumbens, indicating it would not have motoric or drug abuse liabilities. [1]

Reference:
Bymaster FP, Katner JS, Nelson DL et al.  Atomoxetine increases extracellular levels of norepinephrine and dopamine in prefrontal cortex of rat: a potential mechanism for efficacy in attention deficit/hyperactivity disorder. Neuropsychopharmacology. 2002 Nov;27(5):699-711.