Figure 1.

Passive and carrier-mediated flux of diphenhydramine at the rat luminal BBB. Total flux (J_in; nmol s⁻¹ g⁻¹; dashed line), reported as mean ± SD, measured in the rat right brain hemisphere (n = 4–5 animals per concentration) and fitted to total diphenhydramine concentrations in Krebs carbonate perfusion fluid at pH 7.40. The straight solid line represents the passive diffusion flux for diphenhydramine. The dotted line represents data fitted to the carrier-mediated Michaelis–Menten equation by nonlinear least-squares regression obtained by subtracting the passive flux from the total flux (dashed line).