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. 2014 Dec 22;18(1):pyu001. doi: 10.1093/ijnp/pyu001

Figure 4.

Figure 4.

Effect of the modulation of extracellular (pHe) and intracellular (pHi) pH on cocaine transport in hCMEC/D3 cells. a, Effects of changes in the incubation buffer pHe. [3H]-Cocaine uptake was measured for 5 minutes in KH buffer adjusted to pH 5.40, 6.40, or 7.40. *** P<0.001 compared with the pH 5.4 group, and ### P<0.001 for a comparison between pH 6.40 and 7.40 (n=3–4). b, Modulation of pHi with NH4Cl. In pulse condition (cellular alkalinization): after 30 minutes of the usual preincubation, a solution (pHe 7.40) with NH4Cl (30mM) and containing [3H]-cocaine was added for 5 minutes. The NH4Cl prepulse condition (cellular acidification) was obtained by preincubating cells with the incubation buffer (pHe 7.40) plus NH4Cl (30mM) for 15 minutes. Then, the incubation medium was replaced by the usual KH buffer without NH4Cl for 5 minutes. [3H]-Cocaine uptake was measured in the usual KH incubation buffer for 5 minutes (n=3–4).