Assay Method Information
Assay Name:  [3H]DA and [3H]5-HT Uptake Assay
Description:  [3H]DA and [3H]5-HT uptake into striatal synaptosomes was determined to evaluate compound inhibition of the dopamine transporter (DAT) and the serotonin transporter (SERT), respectively. Striata from individual rats were homogenized in ice-cold sucrose solution containing 5 mM NaHCO3 (pH 7.4), with 16 up-and-down strokes of a Teflon pestle homogenizer (clearance≈0.003″). Homogenates were centrifuged at 2000 g for 10 min at 4° C., and resulting supernatants were centrifuged at 20.000 g for 17 min at 4° C. Pellets were resuspended in 2.4 mL (for DAT assays) or 1.5 mL (for SERT assays) of assay buffer (125 mM NaCl, 5 mM KCl, 1.5 mM MgSO4, 1.25 mM CaCl2, 1.5 mM KH2PO4, 10 mM alpha-D-glucose, 25 mM HEPES, 0.1 mM EDTA, 0.1 mM pargyline, 0.1 mM ascorbic acid, saturated with 95% O2/5% CO2, pH 7.4). Assays were performed in duplicate in a total volume of 500 μL (for DAT assays) or 250 μL (for SERT assays). Aliquots of the synaptosomal suspension (25 μL for DAT, 50 μL for SERT) were added to tubes containing assay buffer and various concentrations of analog (1 nM-100 μM), and incubated at 34° C. for 5 min. Nonspecific uptake was determined in the presence of nomifensine (10 μM) for DAT assays or fluoxetine (10 μM) for SERT assays. GBR-12935 (100 nM) was included in the assay buffer for the SERT assay to maximally inhibit [3H]5-HT uptake through DAT and isolate uptake to SERT. Samples were placed on ice, and 50 μL of 0.1 μM [3H]DA (for DAT assays) or 25 μL of 0.1 μM [3H]5-HT (for SERT assays) was added to each tube, and incubated for 10 min at 34° C. Reactions were terminated by addition of 3 mL of ice-cold assay buffer and subsequent filtration and radioactivity retained by the filters was determined by liquid scintillation spectrometry (Tri-Carb 2100TR liquid scintillation analyzer; PerkinElmer Life and Analytical Sciences, Boston, MA).
Affinity data for this assay
 
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