Figure 1

Diphenhydramine uptake by hCMEC/D3 cells. (A) Time course of the cell-to-medium (C/M) ratio of diphenhydramine uptake by hCMEC/D3 cells. Uptake of diphenhydramine (30 μM) was measured at 37°C. (B) Concentration-dependence of the initial uptake rate of diphenhydramine in hCMEC/D3 cells. hCMEC/D3 cells were preincubated with incubation buffer (122 mM NaCl, 3 mM KCl, 25 mM NaHCO₃, 1.2 mM MgSO₄, 1.4 mM CaCl₂, 10 mM D-glucose, 10 mM HEPES, pH 7.4) for 20 min at 37°C. Uptake of diphenhydramine (30 μM) was measured at 37°C for 15 sec. (C) Eadie-Hofstee plot of diphenhydramine uptake by hCMEC/D3 cells. V, initial uptake rate (nmol/mg protein/15 sec). [S], diphenhydramine concentration in the transport medium (μM). Each point represents the mean ± S.E. from three to four determinations. When verticals are not shown, the S.E. is contained within the limits of the symbols.