Question: How is OCT3 associated with serotonin?

Context:
The organic cation transporter 3 (OCT3) is a widely expressed transporter for endogenous and exogenous organic cations. Of particular interest is OCT3 expression and function in the brain, where it plays a role in serotonin clearance and influences mood and behavior. 
Interestingly, OCT3 mRNA is however also significantly up-regulated in the hippocampus of serotonin transporter knockout mice where it might serve as an alternative reuptake mechanism for serotonin.
Of particular interest is OCT3 expression and function in the brain, where it plays a role in serotonin clearance and influences mood and behavior.
However, OCT3 was determined to be a high-capacity and low-affinity transporter for the neurotransmitters dopamine (DA), norepinephrine (NE), and serotonin (5-HT).
Organic cation transporter 3 (OCT3) is a high-capacity, low-affinity transporter that mediates bidirectional, sodium-independent transport of dopamine, norepinephrine, epinephrine, serotonin, and histamine.
The effect of blockade of either 5-hydroxytryptamine (5-HT)/serotonin transporter (SERT) with citalopram or the organic cation transporter 3 (OCT3)/plasma membrane monoamine transporter (PMAT) with decynium-22 (D-22) on spontaneous and evoked release of 5-HT in the nucleus tractus solitarius (NTS) was investigated in rat brainstem slices treated with gabazine
Of particular interest is OCT3 expression and function in the brain, where it plays a role in serotonin clearance and influences mood and behavior
However, OCT3 was determined to be a high-capacity and low-affinity transporter for the neurotransmitters dopamine (DA), norepinephrine (NE), and serotonin (5-HT)
Interestingly, OCT3 mRNA is however also significantly up-regulated in the hippocampus of serotonin transporter knockout mice where it might serve as an alternative reuptake mechanism for serotonin
Organic cation transporter 3 (OCT3) is a high-capacity, low-affinity transporter that mediates bidirectional, sodium-independent transport of dopamine, norepinephrine, epinephrine, serotonin, and histamine
RESULTS: We found a drastic decrease in IL-4 production by stimulated basophils on exposure to serotonin (5-hydroxytryptamine [5-HT]) that is taken up by basophils through the specific high-affinity transporters serotonin transporter and the polyspecific, high-capacity organic cation transporter 3 (OCT3; or Slc22a3) but inhibits their function exclusively through the latter. 
Of particular interest is OCT3 expression and function in the brain, where it plays a role in serotonin clearance and influences mood and behavior. 
However, OCT3 was determined to be a high-capacity and low-affinity transporter for the neurotransmitters dopamine (DA), norepinephrine (NE), and serotonin (5-HT). 
Organic cation transporter 3: Keeping the brake on extracellular serotonin in serotonin-transporter-deficient mice.
Organic cation transporter capable of transporting serotonin is up-regulated in serotonin transporter-deficient mice.
Interestingly, OCT3 mRNA is however also significantly up-regulated in the hippocampus of serotonin transporter knockout mice where it might serve as an alternative reuptake mechanism for serotonin.
Of particular interest is OCT3 expression and function in the brain, where it plays a role in serotonin clearance and influences mood and behavior.
However, OCT3 was determined to be a high-capacity and low-affinity transporter for the neurotransmitters dopamine (DA), norepinephrine (NE), and serotonin (5-HT).
We found a drastic decrease in IL-4 production by stimulated basophils on exposure to serotonin (5-hydroxytryptamine [5-HT]) that is taken up by basophils through the specific high-affinity transporters serotonin transporter and the polyspecific, high-capacity organic cation transporter 3 (OCT3; or Slc22a3) but inhibits their function exclusively through the latter.

Answer: OCT3 plays a role in serotonin clearance
Exact answer: serotonin clearance