Figure 4.

Neurotransmitter uptake activity of mOct2, mOct3, and mPmat in the presence or absence of extracellular Na⁺/Cl⁻. CHO‐K1 cells overexpressing mOct2 (A), mOct3 (B), and mPmat (C) were incubated in normal KRPH buffer, Na⁺‐free buffer, or Cl⁻‐free KRPH buffer containing 10 μm noradrenaline (A‐1, B‐1, C‐1), dopamine (B‐2, C‐2), serotonin (B‐3, C‐3), and histamine (A‐2, B‐4, C‐4) for 5 min at 37 °C. Transport activities were expressed relative to those in normal KRPH buffer. Differences were identified using Student's t tests; *P < 0.05, **P < 0.01, and ***P < 0.001, respectively, Individual transport assays were performed in triplicate (three wells were analyzed for each group per trial). The results were confirmed at least two times in separate experiments using different cryopreserved cell vials. The results shown are representative of experiments performed.