Abstract
Dopaminergic neurotransmission has been investigated extensively, yet direct optical probing of dopamine has not been possible in live cells. Here we image intracellular dopamine with sub-micrometer three-dimensional resolution by harnessing its intrinsic mid-ultraviolet (UV) autofluorescence. Two-photon excitation with visible light (540 nm) in conjunction with a non-epifluorescent detection scheme is used to circumvent the UV toxicity and the UV transmission problems. The method is established by imaging dopamine in a dopaminergic cell line and in control cells (glia), and is validated by mass spectrometry. We further show that individual dopamine vesicles/vesicular clusters can be imaged in cultured rat brain slices, thereby providing a direct visualization of the intracellular events preceding dopamine release induced by depolarization or amphetamine exposure. Our technique opens up a previously inaccessible mid-ultraviolet spectral regime (excitation ∼ 270 nm, emission < 320 nm) for label-free imaging of native molecules in live tissue.
Original language | English (US) |
---|---|
Pages (from-to) | 329-334 |
Number of pages | 6 |
Journal | ACS Chemical Neuroscience |
Volume | 5 |
Issue number | 5 |
DOIs | |
State | Published - May 21 2014 |
Keywords
- Two-photon imaging
- dopaminergic neurons
- intrinsic fluorescence
- neurotransmitter imaging
- ultraviolet microscopy