Figure 3

Nicotine-induced activation of ERK is blocked by the NADPH oxidase inhibitors apocynin and DPI. Hippocampal slice cultures were pretreated for 25 or 55 min with media in the presence or absence of either 100 μM apocynin (A) or 10 μM DPI (B), followed by incubation with nicotine (500 nM, 10 min). A, B) Western blots. Phospho-ERK immunoreactivity was normalized to total ERK and expressed as percent of control. Data represent the mean ± SEM; n = 6-8; * p < 0.01, ** p < 0.001. C) Immunocytochemistry. Confocal images of hippocampal area CA1 were obtained from slices that were double labeled using antibodies specific for phospho-ERK (red) and the neuronal marker NeuN (green). Dual labeling is indicated by yellow/orange. Images were taken with a 20× objective and the scale bar represents 20 μm.