2.4. Determination of 3H-Dopamine Uptake

³H-dopamine uptake was measured as previously described by us [20]. Briefly, tissues were placed in 2.0 mL SKB incubation medium in a Dubnoff incubator and preincubated at 37°C, pH 7.40, and bubbled with a gaseous mixture of 95% O₂ and 5% CO₂ for 15 min; nomifensine (50 μM) was added in the preincubation medium to avoid neuronal dopamine uptake. Thereafter, tissues were transferred to fresh SKB and incubated, in similar conditions, with 0.625 μCi/mL of ³H-dopamine (22.32 nM), 50 μM nomifensine, and the different inhibitors for 15 min. After that time, CNP or Ang-(1-7) was added to the medium and the incubation continued for another 30 min. Control groups were incubated in the absence of the peptides. The following experiments were carried out in samples of renal cortex.