Caco-2 and T-84 Cells 5-HT Uptake

Uptake of [³H]5-HT by Caco-2 cells and T-84 cells under unstimulated conditions was measured by assessing Na⁺- and Cl⁻ dependent [³H]5-HT uptake as previously described by us^{60 (link)}. [³H]5-HT uptake was initiated by the addition of 300 μl of uptake buffer containing 25–50 nM [³H]5-HT (Perkin Elmer) for a time period of 5 min (linear range of uptake). The uptake was stopped by washing twice with ice-chilled 1X PBS. The cells were lysed completed by 500 μl 0.5 N NaOH overnight at 4 °C. Radioactivity was measured with a liquid scintillation counter (Packard) and relative protein levels were measured by Bradford (Bio-Rad).