Rational optimization and imaging in vivo of a genetically encoded optical voltage reporter

Lucas Sjulson, Gero Miesenböck

Research output: Contribution to journalArticle

42 Scopus citations

Abstract

The hybrid voltage sensor (hVOS) combines membrane-targeted green fluorescent protein and the hydrophobic anion dipicrylamine (DPA) to provide a promising tool for optical recording of electrical activity from genetically defined populations of neurons. However, large fluorescence signals are obtained only at high DPA concentrations (>3 μM) that increase membrane capacitance to a level that suppresses neural activity. Here, we develop a quantitative model of the sensor to guide its optimization and achieved an approximate threefold increase in fractional fluorescence change at a lower DPA concentration of 2 μM. Using this optimized voltage reporter, we perform optical recordings of evoked activity in the Drosophila antennal lobe with millisecond temporal resolution but fail to detect action potentials, presumably because spike initiation and/or propagation are inhibited by the capacitive load added even at reduced DPA membrane densities. We evaluate strategies for potential further improvement of hVOS quantitatively and derive theoretical performance limits for optical voltage reporters in general.

Original languageEnglish (US)
Pages (from-to)5582-5593
Number of pages12
JournalJournal of Neuroscience
Volume28
Issue number21
DOIs
StatePublished - May 21 2008
Externally publishedYes

Keywords

  • Fluorescence
  • Membrane capacitance
  • Membrane potential
  • Multiphoton microscopy
  • Neuroimaging
  • Protein-based sensor

ASJC Scopus subject areas

  • Neuroscience(all)

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