title: Two-photon excitation of potentiometric probes enables optical recording of action potentials from mammalian nerve terminals in situ.
abstract: We report the first optical recordings of action potentials, in single trials, from one or a few (approximately 1-2 microm) mammalian nerve terminals in an intact in vitro preparation, the mouse neurohypophysis. The measurements used two-photon excitation along the "blue" edge of the two-photon absorption spectrum of di-3-ANEPPDHQ (a fluorescent voltage-sensitive naphthyl styryl-pyridinium dye), and epifluorescence detection, a configuration that is critical for noninvasive recording of electrical activity from intact brains. Single-trial recordings of action potentials exhibited signal-to-noise ratios of approximately 5:1 and fractional fluorescence changes of up to approximately 10%. This method, by virtue of its optical sectioning capability, deep tissue penetration, and efficient epifluorescence detection, offers clear advantages over linear, as well as other nonlinear optical techniques used to monitor voltage changes in localized neuronal regions, and provides an alternative to invasive electrode arrays for studying neuronal systems in vivo.
authors.affiliation: Department of Neuroscience, University of Pennsylvania School of Medicine, Philadelphia, PA 19104-6074, USA.
authors.forename: Jonathan A N
authors.initials: JA
authors.lastname: Fisher
authors.forename: Jonathan R
authors.initials: JR
authors.lastname: Barchi
authors.forename: Cristin G
authors.initials: CG
authors.lastname: Welle
authors.forename: Gi-Ho
authors.initials: GH
authors.lastname: Kim
authors.forename: Paul
authors.initials: P
authors.lastname: Kosterin
authors.forename: Ana Lía
authors.initials: AL
authors.lastname: Obaid
authors.forename: Arjun G
authors.initials: AG
authors.lastname: Yodh
authors.forename: Diego
authors.initials: D
authors.lastname: Contreras
authors.forename: Brian M
authors.initials: BM
authors.lastname: Salzberg
mesh_terms: D000200:Action Potentials / Q000187:drug effects / Q000502:physiology*; D000818:Animals; D005260:Female; D005453:Fluorescence; D005456:Fluorescent Dyes / Q000494:pharmacology*; D066298:In Vitro Techniques; D051379:Mice; D046529:Microscopy, Electron, Transmission / Q000379:methods; D009474:Neurons / Q000166:cytology* / Q000187:drug effects / Q000502:physiology; D052716:Pituitary Gland, Intermediate / Q000166:cytology; D017729:Presynaptic Terminals / Q000187:drug effects* / Q000648:ultrastructure; D011726:Pyridinium Compounds / Q000494:pharmacology*; D013050:Spectrometry, Fluorescence / Q000379:methods
chemical_list: D005456:Fluorescent Dyes; D011726:Pyridinium Compounds; C050019:1-(3-sulfonatopropyl)-4-(beta)(2-(di-n-butylamino)-6-naphthylvinyl)pyridinium betaine