title: Label-free dopamine imaging in live rat brain slices.
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.
authors.affiliation: Tata Institute of Fundamental Research , Homi Bhabha Road, Colaba, Mumbai 400005, India.
authors.forename: Bidyut
authors.initials: B
authors.lastname: Sarkar
authors.forename: Arkarup
authors.initials: A
authors.lastname: Banerjee
authors.forename: Anand Kant
authors.initials: AK
authors.lastname: Das
authors.forename: Suman
authors.initials: S
authors.lastname: Nag
authors.forename: Sanjeev Kumar
authors.initials: SK
authors.lastname: Kaushalya
authors.forename: Umakanta
authors.initials: U
authors.lastname: Tripathy
authors.forename: Mohammad
authors.initials: M
authors.lastname: Shameem
authors.forename: Shubha
authors.initials: S
authors.lastname: Shukla
authors.forename: Sudipta
authors.initials: S
authors.lastname: Maiti
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001921:Brain / Q000166:cytology* / Q000378:metabolism*; D002478:Cells, Cultured; D004298:Dopamine / Q000378:metabolism*; D066298:In Vitro Techniques; D013058:Mass Spectrometry; D051379:Mice; D008860:Microscopy, Ultraviolet; D009457:Neuroglia / Q000502:physiology; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D061848:Optical Imaging; D051381:Rats; D018490:Serotonin Agents / Q000494:pharmacology; D013997:Time Factors; D010133:p-Chloroamphetamine / Q000494:pharmacology
chemical_list: D018490:Serotonin Agents; D010133:p-Chloroamphetamine; D004298:Dopamine