The use of pHluorins for optical measurements of presynaptic activity

Biophys J. 2000 Oct;79(4):2199-208. doi: 10.1016/S0006-3495(00)76468-X.


Genetically encoded reporters for optical measurements of presynaptic activity hold significant promise for measurements of neurotransmission within intact or semi-intact neuronal networks. We have characterized pH-sensitive green fluorescent protein-based sensors (pHluorins) of synaptic vesicle cycling at nerve terminals. pHluorins have a pK approximately 7.1, which make them ideal for tracking synaptic vesicle lumen pH upon cycling through the plasma membrane during action potentials. A theoretical analysis of the expected signals using this approach and guidelines for future reporter development are provided.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Action Potentials
  • Animals
  • Biophysical Phenomena
  • Biophysics
  • Endocytosis
  • Exocytosis
  • Green Fluorescent Proteins
  • Hippocampus / metabolism
  • Hydrogen-Ion Concentration
  • In Vitro Techniques
  • Luminescent Proteins / metabolism*
  • Models, Neurological
  • Optics and Photonics
  • Presynaptic Terminals / metabolism*
  • Rats
  • Rats, Sprague-Dawley
  • Synaptic Transmission


  • Luminescent Proteins
  • Green Fluorescent Proteins