Figure 4.

Inhibition of soluble TNF signaling attenuates 6-OHDA-induced death of DA neurons in EVM cultures. a, Production of solTNF into culture medium elicited by 6-OHDA [0 μm (white), 20 μm (gray), or 50 μm (black)] in rat E14 ventral mesencephalon (EVM) neuron/glia cultures was measured by quantitative ELISA. b, EVM cultures were treated with 6-hydroxydopamine (20 μm) for 24 h in medium supplemented with 2.5% FBS (see Materials and Methods) in the presence or absence of the solTNF-selective XENP345 (200 ng/ml) or etanercept (200 ng/ml). DA neuron survival was assessed 96 h after exposure to 6-OHDA. DA neurons were identified as double-labeled TH/MAP2b cells. Representative panels are shown for vehicle-, 6-OHDA-, 6-OHDA/XENP345-, or 6-OHDA/etanercept-treated cultures. Scale bar, 100 μm. c, Uptake of [³H]dopamine was measured in 6-OHDA-treated EVM cultures in the presence or absence of TNF inhibitors. Values shown are background-corrected for nonspecific uptake measured by including mazindol during incubation with the tritiated neurotransmitter. Values shown are mean ± SEM; histogram bars with different letters are significantly different (p < 0.05).