Microglial uptake of QDs occurs through mannose receptors and macrophage scavenger receptors. A. The internalization of QDs by microglia in rat primary mixed cortical cultures was quantified by fluorescence intensity with Metamorph software. Microglial uptake of QDs was blocked in a dose-dependent manner by mannan, an inhibitor of mannose receptors (A) and by polyinosinic acid (PIA), an inhibitor of scavenger receptors (B). n = 120-200 cells from at least eight separate images. Experiments were repeated three times. C. Antibodies against mannose receptor (MR) or macrophage scavenger receptor (MSR) were applied to rat primary mixed cortical cultures at a 2 μM concentration for 2 h before incubation with QDs. Microglial uptake of QDs was blocked by antibodies against MR and MSR. n = 105-120 cells from at least eight separate images. Experiments were repeated twice. ***P < 0.001, **P < 0.01, *P < 0.05 vs. control-treated, one-way ANOVA with Tukey-Kramer posthoc analyses. Bars represent mean ± SEM.