Iron is localized within dopamine neurovesicles.

Visible light microscopy of freeze-dried cells (A), and epifluorescence microscopy of the same freeze-dried cells (B) enable the identification of dopamine distribution, while synchrotron X-ray fluorescence nano-imaging reveals the distribution of iron (C, D). Panels C and D represent comparison of the same region imaged in a fluorescent mode to visualize dopamine and with X-ray fluorescence to localize iron. Dopamine and iron are co-located within 200 nm structures characteristic of dopamine neurovesicles as identified by epifluorescence microscopy. A large number of iron and dopamine neurovesicles are found in neurite outgrowths (C) and distal ends (D). Min-max range bar units are arbitrary. Scale bars = 1 µm.